pág. 201
"ETIOLOGÍA DE LA PANCREATITIS AGUDA
GRAVE Y MORTALIDAD EN PACIENTES DEL HGZ
No.46."
“ETIOLOGY OF SEVERE ACUTE PANCREATITIS AND MORTALITY
IN PATIENTS AT HGZ NO. 46.”
Cesar Augusto Cabrera Zacarias
Instituto Mexicano del Seguro Social
Efraín Alejandro Chávez Mollinedo
Instituto Mexicano del Seguro Social
Griselda Hernández Ramírez
Universidad Juárez Autónoma de Tabasco
pág. 202
DOI: https://doi.org/10.37811/cl_rcm.v10i1.22084
Retroperitoneal synovial sarcoma a diagnostic challenge: an uncommon case
Natalia Lasprilla Mogollón1
Nati.lasprilla@gmail.com
https://orcid.org/0009-0009-1488-8980
Especialista en entrenamiento Cirugía de Seno y
tejidos blandos – Instituto Nacional de
Cancerología
Erika Benito Florez
Erikabenito16@gmail.com
https://orcid.org/0000-0002-3031-003X
Especialista en entrenamiento Cirugía de Seno y
tejidos blandos – Instituto Nacional de
Cancerología
Mauricio García Mora
magarcia@cancer.gov.co
https://orcid.org/0000-0003-4529-4033
Director programa de Cirugía Oncológica,
Instituto Nacional de Cancerología y Universidad
Militar Nueva Granada
Especialista en Cirugía Oncológica
Sandra Esperaza Díaz Casas
sdiaz@cancer.gov.co
http://orcid.org/0000-0002-6359-1632
Coordinadora Unidad Funcional de Seno y
Tejidos Blandos, Instituto Nacional de
Cancerología
Especialista en Cirugía de Sento y Tejidos
Blandos
Patricia Lopez Correa
pattylopez5c@gmail.com
http://orcid.org/0000-0002-6220-0062
Patóloga Oncóloga, Instituto Nacional de
Cancerología
Especialista en Patología Oncológica
Laura C. Arce Polania
lauraarcepolania29@gmail.com
https://orcid.org/0000-0001-9760-3251
Filiación Institucional: Residente de Cirugía
General, Universidad Militar Nueva Granada
Emma Gómez Trujillo
emmacristy14@gmail.com
https://orcid.org/0000-0002-0976-7481
Filiación Institucional: Especialista en
entrenamiento Cirugía de Seno y tejidos blandos
– Instituto Nacional de Cancerología
1 Autor principal
Correspondencia: Nati.lasprilla@gmail.com
DOI: https://doi.org/10.37811/cl_rcm.v10i1.22084
Retroperitoneal synovial sarcoma a diagnostic challenge: an uncommon case
Natalia Lasprilla Mogollón1
Nati.lasprilla@gmail.com
https://orcid.org/0009-0009-1488-8980
Especialista en entrenamiento Cirugía de Seno y
tejidos blandos – Instituto Nacional de
Cancerología
Erika Benito Florez
Erikabenito16@gmail.com
https://orcid.org/0000-0002-3031-003X
Especialista en entrenamiento Cirugía de Seno y
tejidos blandos – Instituto Nacional de
Cancerología
Mauricio García Mora
magarcia@cancer.gov.co
https://orcid.org/0000-0003-4529-4033
Director programa de Cirugía Oncológica,
Instituto Nacional de Cancerología y Universidad
Militar Nueva Granada
Especialista en Cirugía Oncológica
Sandra Esperaza Díaz Casas
sdiaz@cancer.gov.co
http://orcid.org/0000-0002-6359-1632
Coordinadora Unidad Funcional de Seno y
Tejidos Blandos, Instituto Nacional de
Cancerología
Especialista en Cirugía de Sento y Tejidos
Blandos
Patricia Lopez Correa
pattylopez5c@gmail.com
http://orcid.org/0000-0002-6220-0062
Patóloga Oncóloga, Instituto Nacional de
Cancerología
Especialista en Patología Oncológica
Laura C. Arce Polania
lauraarcepolania29@gmail.com
https://orcid.org/0000-0001-9760-3251
Filiación Institucional: Residente de Cirugía
General, Universidad Militar Nueva Granada
Emma Gómez Trujillo
emmacristy14@gmail.com
https://orcid.org/0000-0002-0976-7481
Filiación Institucional: Especialista en
entrenamiento Cirugía de Seno y tejidos blandos
– Instituto Nacional de Cancerología
1 Autor principal
Correspondencia: Nati.lasprilla@gmail.com
pág. 203
INTRODUCTION
Synovial sarcoma (SS) is a rare and aggressive mesenchymal neoplasm that can arise at various
anatomical sites. However, it typically occurs in the soft tissues of the extremities, particularly the lower
limbs [1]. This tumor makes up 0.8%-10% of soft tissue sarcomas and about 1% of reported
retroperitoneal tumors. [2,3,4]. Its highest incidence is observed in young adults, with no clear
differences by sex. Because of its low frequency, epidemiological data are primarily derived from
isolated reports and small series. [2,3,4,5]. Although its name suggests a synovial origin, the tumor does
not develop from the synovial membrane; the term is kept because of morphological similarities to
embryonic synovium [6,7]. Its diagnosis is difficult, not only because it can resemble benign lesions,
but also because of morphological overlap with other sarcomas. When it occurs in the retroperitoneum,
its detection is often delayed because this anatomical space allows for progressive tumor growth without
specific symptoms. Retroperitoneal lesions can resemble other aggressive neoplasms; this complicates
differential diagnosis and leads to significant treatment delays, which negatively affect prognosis. In
this context, most retroperitoneal cases are detected at advanced stages and are linked to lower survival
rates, estimated at 20%-29% at five years [4, 6].Retroperitoneal SS is extremely rare, with fewer than
35 cases documented in the literature [4,5]. Spinal involvement is exceptional, and most reports lack or
have limited follow-up [2]. Due to the absence of standardized guidelines for retroperitoneal SS—the
National Comprehensive Cancer Network (NCCN), the European Society for Medical Oncology
(ESMO), and the American Society of Clinical Oncology (ASCO) include this tumor within the general
management of soft tissue sarcomas—its approach, diagnosis, and treatment pose a challenge for
surgeons [1,2].
Keywords: synovial sarcoma, retroperitoneum, mesenchymal neoplasm, differential diagnosis, and
prognosis.
INTRODUCTION
Synovial sarcoma (SS) is a rare and aggressive mesenchymal neoplasm that can arise at various
anatomical sites. However, it typically occurs in the soft tissues of the extremities, particularly the lower
limbs [1]. This tumor makes up 0.8%-10% of soft tissue sarcomas and about 1% of reported
retroperitoneal tumors. [2,3,4]. Its highest incidence is observed in young adults, with no clear
differences by sex. Because of its low frequency, epidemiological data are primarily derived from
isolated reports and small series. [2,3,4,5]. Although its name suggests a synovial origin, the tumor does
not develop from the synovial membrane; the term is kept because of morphological similarities to
embryonic synovium [6,7]. Its diagnosis is difficult, not only because it can resemble benign lesions,
but also because of morphological overlap with other sarcomas. When it occurs in the retroperitoneum,
its detection is often delayed because this anatomical space allows for progressive tumor growth without
specific symptoms. Retroperitoneal lesions can resemble other aggressive neoplasms; this complicates
differential diagnosis and leads to significant treatment delays, which negatively affect prognosis. In
this context, most retroperitoneal cases are detected at advanced stages and are linked to lower survival
rates, estimated at 20%-29% at five years [4, 6].Retroperitoneal SS is extremely rare, with fewer than
35 cases documented in the literature [4,5]. Spinal involvement is exceptional, and most reports lack or
have limited follow-up [2]. Due to the absence of standardized guidelines for retroperitoneal SS—the
National Comprehensive Cancer Network (NCCN), the European Society for Medical Oncology
(ESMO), and the American Society of Clinical Oncology (ASCO) include this tumor within the general
management of soft tissue sarcomas—its approach, diagnosis, and treatment pose a challenge for
surgeons [1,2].
Keywords: synovial sarcoma, retroperitoneum, mesenchymal neoplasm, differential diagnosis, and
prognosis.
pág. 204
Sarcoma sinovial retroperitoneal: un reto diagnóstico: un caso poco común
ABSTRACT
El sarcoma sinovial (SS) es una neoplasia mesenquimal rara y agresiva que puede surgir en diversos
sitios anatómicos. Sin embargo, típicamente ocurre en los tejidos blandos de las extremidades,
particularmente en las extremidades inferiores [1]. Este tumor representa el 0.8%-10% de los sarcomas
de tejidos blandos y aproximadamente el 1% de los tumores retroperitoneales reportados [2,3,4]. Su
mayor incidencia se observa en adultos jóvenes, sin diferencias claras por sexo. Debido a su baja
frecuencia, los datos epidemiológicos provienen principalmente de informes aislados y series cortas
[2,3,4,5]. Aunque su nombre sugiere un origen sinovial, el tumor no se desarrolla a partir de la membrana
sinovial; el término se mantiene debido a las similitudes morfológicas con la membrana sinovial
embrionaria [6,7]. Su diagnóstico es difícil, no solo porque puede parecerse a lesiones benignas, sino
también por la superposición morfológica con otros sarcomas. Cuando ocurre en el retroperitoneo, su
detección a menudo se retrasa porque este espacio anatómico permite el crecimiento progresivo del
tumor sin síntomas específicos. Las lesiones retroperitoneales pueden parecerse a otras neoplasias
agresivas; esto complica el diagnóstico diferencial y conduce a retrasos significativos en el tratamiento,
lo que afecta negativamente el pronóstico. En este contexto, la mayoría de los casos retroperitoneales se
detectan en etapas avanzadas y están vinculados a tasas de supervivencia más bajas, estimadas en 20%-
29% a los cinco años [4, 6]. El SS retroperitoneal es extremadamente raro, con menos de 35 casos
documentados en la literatura [4,5]. La afectación espinal es excepcional, y la mayoría de los informes
carecen de seguimiento o tienen un seguimiento limitado [2]. Debido a la ausencia de pautas
estandarizadas para el SS retroperitoneal (la National Comprehensive Cancer Network [NCCN], la
European Society for Medical Oncology [ESMO] y la American Society of Clinical Oncology [ASCO])
incluyen este tumor dentro del manejo general de los sarcomas de tejidos blandos), su abordaje,
diagnóstico y tratamiento representan un desafío para los cirujanos [1,2].
Palabras clave: sarcoma sinovial, retroperitoneo, neoplasia mesenquimal, diagnóstico diferencial y
pronóstico.
Artículo recibido 10 diciembre 2025
Aceptado para publicación: 10 enero 2026
Sarcoma sinovial retroperitoneal: un reto diagnóstico: un caso poco común
ABSTRACT
El sarcoma sinovial (SS) es una neoplasia mesenquimal rara y agresiva que puede surgir en diversos
sitios anatómicos. Sin embargo, típicamente ocurre en los tejidos blandos de las extremidades,
particularmente en las extremidades inferiores [1]. Este tumor representa el 0.8%-10% de los sarcomas
de tejidos blandos y aproximadamente el 1% de los tumores retroperitoneales reportados [2,3,4]. Su
mayor incidencia se observa en adultos jóvenes, sin diferencias claras por sexo. Debido a su baja
frecuencia, los datos epidemiológicos provienen principalmente de informes aislados y series cortas
[2,3,4,5]. Aunque su nombre sugiere un origen sinovial, el tumor no se desarrolla a partir de la membrana
sinovial; el término se mantiene debido a las similitudes morfológicas con la membrana sinovial
embrionaria [6,7]. Su diagnóstico es difícil, no solo porque puede parecerse a lesiones benignas, sino
también por la superposición morfológica con otros sarcomas. Cuando ocurre en el retroperitoneo, su
detección a menudo se retrasa porque este espacio anatómico permite el crecimiento progresivo del
tumor sin síntomas específicos. Las lesiones retroperitoneales pueden parecerse a otras neoplasias
agresivas; esto complica el diagnóstico diferencial y conduce a retrasos significativos en el tratamiento,
lo que afecta negativamente el pronóstico. En este contexto, la mayoría de los casos retroperitoneales se
detectan en etapas avanzadas y están vinculados a tasas de supervivencia más bajas, estimadas en 20%-
29% a los cinco años [4, 6]. El SS retroperitoneal es extremadamente raro, con menos de 35 casos
documentados en la literatura [4,5]. La afectación espinal es excepcional, y la mayoría de los informes
carecen de seguimiento o tienen un seguimiento limitado [2]. Debido a la ausencia de pautas
estandarizadas para el SS retroperitoneal (la National Comprehensive Cancer Network [NCCN], la
European Society for Medical Oncology [ESMO] y la American Society of Clinical Oncology [ASCO])
incluyen este tumor dentro del manejo general de los sarcomas de tejidos blandos), su abordaje,
diagnóstico y tratamiento representan un desafío para los cirujanos [1,2].
Palabras clave: sarcoma sinovial, retroperitoneo, neoplasia mesenquimal, diagnóstico diferencial y
pronóstico.
Artículo recibido 10 diciembre 2025
Aceptado para publicación: 10 enero 2026
pág. 205
CASE PRESENTATION
A 49-year-old male patient with a history of classic seminoma with an atypical component, treated at
age 34 in 2009 and currently in complete remission, with no other significant oncological history or
comorbidities. He consulted the Instituto Nacional de Cancerología (INC) (Bogotá, Colombia) in 2025
due to a six-month history of progressive left dorso-lumbar pain radiating to the inguinal region and the
ipsilateral lower limb, along with intermittent episodes of paresthesia.
On physical examination, the obese patient (120 kg, 1.75 m), with increased subcutaneous fat, had a
ventral hernia M2M3W2 from a previous laparotomy, and no evidence of a palpable abdominal or
lumbar mass. There was no edema in the lower extremities, no signs of peripheral vascular compression,
nor loss of strength or neurological alterations.
Outside the INC, it was considered a relapse of retroperitoneal lymph node after initial oncological
pathology; however, because of the discrepancy between the clinical presentation and the timing, he
was referred to the Breast and Soft Tissue Surgery team.
Imaging studies were ordered to characterize the lesion and assess its extent. A contrast-enhanced
computed tomography (CT) scan of the abdomen and pelvis showed a large left retroperitoneal mass in
the para-aortic infrarenal space, measuring 71 x 39 x 43 mm. The lesion displaced the duodenum and
aorta to the right, medializing the retroperitoneal structures. In addition, a magnetic resonance imaging
(MRI) scan of the lumbosacral spine revealed a solid mass involving the psoas muscle from L2 to L4
and in close contact with the L3 vertebral foramen, resulting in a pathological fracture with 50% wedging
of the vertebral body (Figures 1 and 2).
Given the complex location and bone involvement, two inconclusive image-guided biopsies were
needed; ultimately, the histopathological report was consistent with SS.
CASE PRESENTATION
A 49-year-old male patient with a history of classic seminoma with an atypical component, treated at
age 34 in 2009 and currently in complete remission, with no other significant oncological history or
comorbidities. He consulted the Instituto Nacional de Cancerología (INC) (Bogotá, Colombia) in 2025
due to a six-month history of progressive left dorso-lumbar pain radiating to the inguinal region and the
ipsilateral lower limb, along with intermittent episodes of paresthesia.
On physical examination, the obese patient (120 kg, 1.75 m), with increased subcutaneous fat, had a
ventral hernia M2M3W2 from a previous laparotomy, and no evidence of a palpable abdominal or
lumbar mass. There was no edema in the lower extremities, no signs of peripheral vascular compression,
nor loss of strength or neurological alterations.
Outside the INC, it was considered a relapse of retroperitoneal lymph node after initial oncological
pathology; however, because of the discrepancy between the clinical presentation and the timing, he
was referred to the Breast and Soft Tissue Surgery team.
Imaging studies were ordered to characterize the lesion and assess its extent. A contrast-enhanced
computed tomography (CT) scan of the abdomen and pelvis showed a large left retroperitoneal mass in
the para-aortic infrarenal space, measuring 71 x 39 x 43 mm. The lesion displaced the duodenum and
aorta to the right, medializing the retroperitoneal structures. In addition, a magnetic resonance imaging
(MRI) scan of the lumbosacral spine revealed a solid mass involving the psoas muscle from L2 to L4
and in close contact with the L3 vertebral foramen, resulting in a pathological fracture with 50% wedging
of the vertebral body (Figures 1 and 2).
Given the complex location and bone involvement, two inconclusive image-guided biopsies were
needed; ultimately, the histopathological report was consistent with SS.
pág. 206
Figure 1. Initial CT scan of the abdomen and pelvis. A. Coronal view: A lobulated mass is visible, with
necrotic changes inside it, near the infrarenal aorta. B. Axial view: Multilobulated mass exhibiting
heterogeneous changes within it, with infiltration of the psoas muscle and the L3 vertebral body. Images
courtesy of INC.
Figure 2. Initial contrast-enhanced lumbar MRI. A. Sagittal view: Tumor lesion with myxoid or cystic
changes of lesser intensity in relation to the heterogeneous component. Displacement of intestinal loops
anteriorly and close contact with paravertebral muscles. B. Axial view: Rounded, lobulated mass with
heterogeneous signal; occupation of the neural foramen is observed, extending into the spinal canal and
displacing the nerve root. In close contact with the edge of the vertebral pedicle.
With the diagnosis established, the case was referred to a multidisciplinary team (Clinical Oncology,
Radiation Oncology, Surgical Oncology, Breast and Soft Tissue Surgery, Neurosurgery, Vascular
Surgery, Radiological Oncology, and Pathological Oncology). The SS was considered greater than 5
Figure 1. Initial CT scan of the abdomen and pelvis. A. Coronal view: A lobulated mass is visible, with
necrotic changes inside it, near the infrarenal aorta. B. Axial view: Multilobulated mass exhibiting
heterogeneous changes within it, with infiltration of the psoas muscle and the L3 vertebral body. Images
courtesy of INC.
Figure 2. Initial contrast-enhanced lumbar MRI. A. Sagittal view: Tumor lesion with myxoid or cystic
changes of lesser intensity in relation to the heterogeneous component. Displacement of intestinal loops
anteriorly and close contact with paravertebral muscles. B. Axial view: Rounded, lobulated mass with
heterogeneous signal; occupation of the neural foramen is observed, extending into the spinal canal and
displacing the nerve root. In close contact with the edge of the vertebral pedicle.
With the diagnosis established, the case was referred to a multidisciplinary team (Clinical Oncology,
Radiation Oncology, Surgical Oncology, Breast and Soft Tissue Surgery, Neurosurgery, Vascular
Surgery, Radiological Oncology, and Pathological Oncology). The SS was considered greater than 5
pág. 207
cm, with borderline resectability criteria due to vertebral involvement (L3) and close contact with the
duodenum, infrarenal aorta, and left iliac vessels. Therefore, the team decided on neoadjuvant
management with MAI chemotherapy (mesna, adriamycin, ifosfamide) for three cycles, followed by
image-guided radiation therapy (IGRT), delivering 55 Gy in five fractions on alternate days. In a new
multidisciplinary team assessment, the follow-up CT scan showed a reduction in tumor volume (65 ×
37 × 45 mm), with no significant changes in lumbar involvement or vascular contact (Figure 3).
Therefore, it was determined that the optimal treatment was a wide surgical resection with simultaneous
control of vertebral involvement, and a two-stage procedure was planned along with the Neurosurgery
service.
Figure 3. Post-neoadjuvant abdominal CT scan. Coronal view: Solid, heterogeneous retroperitoneal
mass. Hypodense areas indicative of necrosis are observed within it, with the contrast medium enhancing
the solid component. It displaces the duodenum and intestinal loops anteriorly and superiorly. It is in
close contact with the abdominal aorta without compromising the inferior vena cava.
In the first surgical stage, a left para-aortic mass measuring 12 × 14 cm was identified, with desmoplastic
changes secondary to neoadjuvant therapy. It was in proximity to the infrarenal aorta, the left iliac
vessels, and the left renal pedicle, without vascular infiltration. However, there was infiltration of the
left ureter in its distal third, without a cleavage plane, and also with involvement of the distal psoas, the
first portion of the jejunum (fixed loop), and the L3 vertebral body.
To achieve the oncological goal, the lesion was meticulously mobilized, dissecting the retroperitoneal
planes while preserving major vascular structures. This involved a partial duodenectomy, resection of
cm, with borderline resectability criteria due to vertebral involvement (L3) and close contact with the
duodenum, infrarenal aorta, and left iliac vessels. Therefore, the team decided on neoadjuvant
management with MAI chemotherapy (mesna, adriamycin, ifosfamide) for three cycles, followed by
image-guided radiation therapy (IGRT), delivering 55 Gy in five fractions on alternate days. In a new
multidisciplinary team assessment, the follow-up CT scan showed a reduction in tumor volume (65 ×
37 × 45 mm), with no significant changes in lumbar involvement or vascular contact (Figure 3).
Therefore, it was determined that the optimal treatment was a wide surgical resection with simultaneous
control of vertebral involvement, and a two-stage procedure was planned along with the Neurosurgery
service.
Figure 3. Post-neoadjuvant abdominal CT scan. Coronal view: Solid, heterogeneous retroperitoneal
mass. Hypodense areas indicative of necrosis are observed within it, with the contrast medium enhancing
the solid component. It displaces the duodenum and intestinal loops anteriorly and superiorly. It is in
close contact with the abdominal aorta without compromising the inferior vena cava.
In the first surgical stage, a left para-aortic mass measuring 12 × 14 cm was identified, with desmoplastic
changes secondary to neoadjuvant therapy. It was in proximity to the infrarenal aorta, the left iliac
vessels, and the left renal pedicle, without vascular infiltration. However, there was infiltration of the
left ureter in its distal third, without a cleavage plane, and also with involvement of the distal psoas, the
first portion of the jejunum (fixed loop), and the L3 vertebral body.
To achieve the oncological goal, the lesion was meticulously mobilized, dissecting the retroperitoneal
planes while preserving major vascular structures. This involved a partial duodenectomy, resection of
pág. 208
the iliopsoas muscle, and, during the same surgical procedure, an L3 corpectomy performed by
Neurosurgery. The mass was resected en bloc, ensuring wide macroscopic margins and taking out
compromised bone fragments associated with the pathological fracture. No significant hemorrhagic
events or iatrogenic injuries occurred during the procedure (Figure 4).
Subsequently, in a second surgical procedure eight days after surgery, the duodenal anastomosis was
revised, and the neurosurgery team completed the L3 corpectomy through the same initial approach.
Following resection of the affected vertebral body, spinal reconstruction was performed with arthrodesis
and bone graft placement—a 45 mm titanium lumbar cylinder (Johnson & Johnson) filled with 6G bone
graft—with proper fluoroscopic verification, restoring mechanical stability (Figure 5). The patient was
transferred to the Intensive Care Unit for recovery under close neurological monitoring. No new deficits
or immediate complications were observed.
Figure 4. Intraoperative findings. A. Intraoperative image showing the retroperitoneal tumor (arrow),
solid and lobulated in appearance, adhered to deep planes and close to vascular structures and the psoas
muscle in the retroperitoneum. B. Tumor surgical bed after complete resection of the retroperitoneal
tumor (arrow). The deep planes are clear, with adequate exposure of retroperitoneal structures and no
macroscopic residual mass. C. Tumor surgical bed after resection of the retroperitoneal sarcoma,
showing the exposed abdominal aorta (green arrow) and the site of vascular and tissue reconstruction in
the area of the resected tumor (yellow arrow). Titanium fixation hardware is visible in the vertebral
body.
B C
the iliopsoas muscle, and, during the same surgical procedure, an L3 corpectomy performed by
Neurosurgery. The mass was resected en bloc, ensuring wide macroscopic margins and taking out
compromised bone fragments associated with the pathological fracture. No significant hemorrhagic
events or iatrogenic injuries occurred during the procedure (Figure 4).
Subsequently, in a second surgical procedure eight days after surgery, the duodenal anastomosis was
revised, and the neurosurgery team completed the L3 corpectomy through the same initial approach.
Following resection of the affected vertebral body, spinal reconstruction was performed with arthrodesis
and bone graft placement—a 45 mm titanium lumbar cylinder (Johnson & Johnson) filled with 6G bone
graft—with proper fluoroscopic verification, restoring mechanical stability (Figure 5). The patient was
transferred to the Intensive Care Unit for recovery under close neurological monitoring. No new deficits
or immediate complications were observed.
Figure 4. Intraoperative findings. A. Intraoperative image showing the retroperitoneal tumor (arrow),
solid and lobulated in appearance, adhered to deep planes and close to vascular structures and the psoas
muscle in the retroperitoneum. B. Tumor surgical bed after complete resection of the retroperitoneal
tumor (arrow). The deep planes are clear, with adequate exposure of retroperitoneal structures and no
macroscopic residual mass. C. Tumor surgical bed after resection of the retroperitoneal sarcoma,
showing the exposed abdominal aorta (green arrow) and the site of vascular and tissue reconstruction in
the area of the resected tumor (yellow arrow). Titanium fixation hardware is visible in the vertebral
body.
B C
pág. 209
Postoperative CT imaging showed adequate vertebral reconstruction, correct positioning of the
arthrodesis material, and no fluid collections, residual bleeding, or involvement of nearby structures.
Subsequent clinical evaluation confirmed progressive improvement in low back pain and resolution of
paresthesias that had prompted the initial consultation.
The patient was discharged with clear instructions for physical rehabilitation and close follow-up by the
Oncology, Soft Tissue Surgery, and Neurosurgery services.
Surgical pathology was consistent with a monophasic synovial sarcoma measuring 11 × 4 × 3.3 cm,
with 40% residual viable cells and 60% hyalinization/sclerosis (Figure 5). The superior, inferior, and
anterior surgical margins were positive (R1); the lateral and medial margins were 0.2 cm and 0.4 cm
from the tumor, respectively, with no lymphatic, vascular, or neural invasion. Immunohistochemistry
showed that the tumor cells were positive for CD99, TLE1, and CK AE1/AE3, negative for SALL4,
OCT4, EMA, and CD30, and had a Ki-67 index of 20%.
Postoperative CT imaging showed adequate vertebral reconstruction, correct positioning of the
arthrodesis material, and no fluid collections, residual bleeding, or involvement of nearby structures.
Subsequent clinical evaluation confirmed progressive improvement in low back pain and resolution of
paresthesias that had prompted the initial consultation.
The patient was discharged with clear instructions for physical rehabilitation and close follow-up by the
Oncology, Soft Tissue Surgery, and Neurosurgery services.
Surgical pathology was consistent with a monophasic synovial sarcoma measuring 11 × 4 × 3.3 cm,
with 40% residual viable cells and 60% hyalinization/sclerosis (Figure 5). The superior, inferior, and
anterior surgical margins were positive (R1); the lateral and medial margins were 0.2 cm and 0.4 cm
from the tumor, respectively, with no lymphatic, vascular, or neural invasion. Immunohistochemistry
showed that the tumor cells were positive for CD99, TLE1, and CK AE1/AE3, negative for SALL4,
OCT4, EMA, and CD30, and had a Ki-67 index of 20%.
pág. 210
Figure 5. Pathology. A-B. Hematoxylin-eosin stain. A mesenchymal neoplasm consisting of spindle
cells with slight atypia arranged in fascicles is observed. Few mitoses are seen. No necrosis is present.
C. Focal staining for AE1/AE3. D. Nuclear staining for TLE1.
The patient was evaluated by the Clinical Oncology service, and follow-up imaging was recommended
due to the risk of local and distant recurrence given planned R1 margins, with no indication for adjuvant
chemotherapy. Systemic management was advised only in the event of progression. At the time of
writing, the patient has shown no signs of local, regional, or distant recurrence and remains under follow-
up with clinical improvement.
Patient perspective and informed consent
From the patient’s perspective, he reported significant improvement in symptoms and functional
recovery after surgery, expressing satisfaction with the treatment received and, in particular, grateful for
the absence of neurological deficits after the intervention.
The patient provided full informed consent for the surgical procedure that included an explanation of
the major neurological and vascular risks. He also signed a specific consent form authorizing the
publication of his clinical case and diagnostic images, in accordance with international ethical standards
and the CARE guidelines.
A B
DC
B
C
Figure 5. Pathology. A-B. Hematoxylin-eosin stain. A mesenchymal neoplasm consisting of spindle
cells with slight atypia arranged in fascicles is observed. Few mitoses are seen. No necrosis is present.
C. Focal staining for AE1/AE3. D. Nuclear staining for TLE1.
The patient was evaluated by the Clinical Oncology service, and follow-up imaging was recommended
due to the risk of local and distant recurrence given planned R1 margins, with no indication for adjuvant
chemotherapy. Systemic management was advised only in the event of progression. At the time of
writing, the patient has shown no signs of local, regional, or distant recurrence and remains under follow-
up with clinical improvement.
Patient perspective and informed consent
From the patient’s perspective, he reported significant improvement in symptoms and functional
recovery after surgery, expressing satisfaction with the treatment received and, in particular, grateful for
the absence of neurological deficits after the intervention.
The patient provided full informed consent for the surgical procedure that included an explanation of
the major neurological and vascular risks. He also signed a specific consent form authorizing the
publication of his clinical case and diagnostic images, in accordance with international ethical standards
and the CARE guidelines.
A B
DC
B
C
pág. 211
DISCUSSION
Synovial sarcoma is a rare malignant tumor that arises in mesenchymal tissues and commonly affects
the extremities of young adults. It makes up 5–10% of soft tissue tumors, with an estimated incidence
of 1 to 1.5 cases per million people annually [3,8]. Its exact incidence remains uncertain due to its low
frequency, and most available data are from case reports or small series [3,6].
Primary retroperitoneal presentation is rare, accounting for less than 1% of sarcomas in this location,
which was first described in 1954 by Pack and Tabah [3,5,9,10]. This rarity poses significant diagnostic
challenges, as the anatomical depth of the retroperitoneum allows the tumor to grow silently until
advanced stages, when vascular or nerve structures are already affected, or neurological pain symptoms
appear, as in this case [3].
Differential diagnoses include liposarcoma, leiomyosarcoma, and undifferentiated pleomorphic
sarcoma [3, 6]. As in this case, it is important to consider the patient’s oncological history to adopt a
comprehensive approach and exclude other retroperitoneal pathologies with lymph node involvement,
such as lymphoma, seminoma, or tumors of gynecological or urothelial origin.
Clinical presentation
The interval between symptom onset and diagnosis can range from 6 months to 10 years [2].
Retroperitoneal SS is often diagnosed late, which worsens the prognosis and poses a challenge for the
surgeon.
The most common symptoms include chronic abdominal or lower back pain, radiation to the extremities,
sensory or motor disturbances, a palpable mass, weight loss, or symptoms caused by compression of
structures such as the bowel, urinary system, or kidneys [2,9]. The study by Yang et al. [2] found that
81.25% of participants had neurological deficits.
Imaging studies
Imaging studies are crucial for characterizing these lesions in order to guide diagnosis, evaluate
resectability, and determine the presence of metastatic involvement [4,6]. The combination of CT and
MRI helps define the tumor's relationship to solid organs, vascular structures, and the spine, which is
essential for surgical planning [3,4].
DISCUSSION
Synovial sarcoma is a rare malignant tumor that arises in mesenchymal tissues and commonly affects
the extremities of young adults. It makes up 5–10% of soft tissue tumors, with an estimated incidence
of 1 to 1.5 cases per million people annually [3,8]. Its exact incidence remains uncertain due to its low
frequency, and most available data are from case reports or small series [3,6].
Primary retroperitoneal presentation is rare, accounting for less than 1% of sarcomas in this location,
which was first described in 1954 by Pack and Tabah [3,5,9,10]. This rarity poses significant diagnostic
challenges, as the anatomical depth of the retroperitoneum allows the tumor to grow silently until
advanced stages, when vascular or nerve structures are already affected, or neurological pain symptoms
appear, as in this case [3].
Differential diagnoses include liposarcoma, leiomyosarcoma, and undifferentiated pleomorphic
sarcoma [3, 6]. As in this case, it is important to consider the patient’s oncological history to adopt a
comprehensive approach and exclude other retroperitoneal pathologies with lymph node involvement,
such as lymphoma, seminoma, or tumors of gynecological or urothelial origin.
Clinical presentation
The interval between symptom onset and diagnosis can range from 6 months to 10 years [2].
Retroperitoneal SS is often diagnosed late, which worsens the prognosis and poses a challenge for the
surgeon.
The most common symptoms include chronic abdominal or lower back pain, radiation to the extremities,
sensory or motor disturbances, a palpable mass, weight loss, or symptoms caused by compression of
structures such as the bowel, urinary system, or kidneys [2,9]. The study by Yang et al. [2] found that
81.25% of participants had neurological deficits.
Imaging studies
Imaging studies are crucial for characterizing these lesions in order to guide diagnosis, evaluate
resectability, and determine the presence of metastatic involvement [4,6]. The combination of CT and
MRI helps define the tumor's relationship to solid organs, vascular structures, and the spine, which is
essential for surgical planning [3,4].
pág. 212
Features that help identify SS on imaging include intratumoral hemorrhage and the presence of
calcifications. On CT scans, calcifications are seen in 27-47% of cases and can also reveal areas of active
bleeding and bone involvement [6–9].
Regarding MRI, it allows identification of a heterogeneous mass with solid or cystic components, caused
by hemorrhage or fibrosis [3–5]. It is important to note that the absence of an intratumoral lipomatous
component on CT or MRI is a key sign for the differential diagnosis between SS and liposarcoma [1,6].
In this patient, the lesion's characteristics, infiltration of the L3 vertebral body, and associated
pathological fracture indicated a locally aggressive behavior rarely described in the literature, which is
consistent with high-grade tumors and rules out differential diagnoses such as lymphoma or regional
recurrence of seminoma in this case. Similarly, bone involvement has been reported only sporadically
in the literature, which could be considered a borderline resectability factor and a poor prognostic
indicator for treatment planning.
Histopathology
The definitive diagnosis requires histopathological confirmation and an immunohistochemical panel.
The morphology of spindle-shaped cells arranged in fascicles strongly indicates monophasic SS. This
type of tumor is often confused with other mesenchymal tumors such as malignant fibroepithelial
tumors, solitary fibrous tumors, and sarcomatoid carcinomas, among others. Therefore,
immunohistochemical and cytogenetic studies are necessary to distinguish SS [4].
Histologically, there are three main subtypes: poorly differentiated, biphasic, and monophasic spindle
cells, the latter being the most common subtype in SS [1, 6,11]. The monophasic spindle cell type
consists of a matrix made up of relatively small spindle cells with a uniform, oval, short nucleus and
long vacuolar structure. The chromatin is evenly dispersed, the nucleus is not prominent, and the
cytoplasm is rarely eosinophilic [1, 6]. Immunohistochemistry typically shows epithelial membrane
antigen (EMA) expression and diffuse Bcl-2 and CD99 expression [1].
Confirmatory diagnosis is achieved through translocation (x;18)(p11;q11) tests, since the SS18-SSX
fusion type is critical due to its high sensitivity and specificity for SS [6,8]. For these tests, the use of
next-generation sequencing (NGS) panels is recommended, as they can help distinguish between SS18-
SSX1 and SS18-SSX2 [10,11]. While there is no strong consensus on the link between fusion subtype
Features that help identify SS on imaging include intratumoral hemorrhage and the presence of
calcifications. On CT scans, calcifications are seen in 27-47% of cases and can also reveal areas of active
bleeding and bone involvement [6–9].
Regarding MRI, it allows identification of a heterogeneous mass with solid or cystic components, caused
by hemorrhage or fibrosis [3–5]. It is important to note that the absence of an intratumoral lipomatous
component on CT or MRI is a key sign for the differential diagnosis between SS and liposarcoma [1,6].
In this patient, the lesion's characteristics, infiltration of the L3 vertebral body, and associated
pathological fracture indicated a locally aggressive behavior rarely described in the literature, which is
consistent with high-grade tumors and rules out differential diagnoses such as lymphoma or regional
recurrence of seminoma in this case. Similarly, bone involvement has been reported only sporadically
in the literature, which could be considered a borderline resectability factor and a poor prognostic
indicator for treatment planning.
Histopathology
The definitive diagnosis requires histopathological confirmation and an immunohistochemical panel.
The morphology of spindle-shaped cells arranged in fascicles strongly indicates monophasic SS. This
type of tumor is often confused with other mesenchymal tumors such as malignant fibroepithelial
tumors, solitary fibrous tumors, and sarcomatoid carcinomas, among others. Therefore,
immunohistochemical and cytogenetic studies are necessary to distinguish SS [4].
Histologically, there are three main subtypes: poorly differentiated, biphasic, and monophasic spindle
cells, the latter being the most common subtype in SS [1, 6,11]. The monophasic spindle cell type
consists of a matrix made up of relatively small spindle cells with a uniform, oval, short nucleus and
long vacuolar structure. The chromatin is evenly dispersed, the nucleus is not prominent, and the
cytoplasm is rarely eosinophilic [1, 6]. Immunohistochemistry typically shows epithelial membrane
antigen (EMA) expression and diffuse Bcl-2 and CD99 expression [1].
Confirmatory diagnosis is achieved through translocation (x;18)(p11;q11) tests, since the SS18-SSX
fusion type is critical due to its high sensitivity and specificity for SS [6,8]. For these tests, the use of
next-generation sequencing (NGS) panels is recommended, as they can help distinguish between SS18-
SSX1 and SS18-SSX2 [10,11]. While there is no strong consensus on the link between fusion subtype
pág. 213
and outcomes, histological grade has been identified as a potentially more significant prognostic factor
[3,8,12].
Multiple studies have identified prognostic factors associated with survival, including age, tumor size,
surgical margins, mitotic index, bone or neurovascular invasion, histological subtype, p53
overexpression, and Ki-67 proliferation index [2,8].
In this specific case, TLE1 positivity and the absence of germline markers helped rule out recurrence of
the previous seminoma. Furthermore, the intermediate proliferation rate (Ki-67 ~20%) aligns with the
aggressive behavior observed on imaging and at surgery, consistent with reports from other series of
this neoplasm.
Treatment justification
Optimal management of these neoplasms requires a multidisciplinary approach at sarcoma referral
centers. Wide surgical resection with negative margins is the cornerstone of treatment and the most
important prognostic factor for survival [12]. Surgical resection may involve multivisceral resection or
resection with planned R1 margins when vascular or nerve structures are affected, provided that
neoadjuvant or adjuvant therapy is administered [2,13]. In the series by Yang et al. [2], en bloc resections
achieved prolonged local control without relapse, with follow-up ranging from 11 to 74 months.
Vertebral involvement remains a topic of discussion, as it includes tumors with borderline resectability.
According to NCCN and ESMO guidelines, histological grade, histological subtype, tumor size, and
involvement of vascular or nerve structures should be considered when deciding on neoadjuvant
management [1,2,11,13]. In our case, the multidisciplinary team determined that the patient met the
criteria for neoadjuvant chemotherapy with an MAI regimen and concurrent radiotherapy, aiming to
improve the likelihood of complete resection and locoregional control.
Preoperative radiotherapy may be considered in retroperitoneal sarcomas (STRASS trial), although its
benefit in specific SS is limited; however, it contributes to improved local control in high-grade tumors
or in cases with vertebral involvement [3, 4,13].
In our case, the patient received neoadjuvant chemotherapy and radiotherapy, and a wide multivisceral
local resection was performed, with planned positive margins (R1) on pathology, to preserve adjacent
structures, improve function, and maintain the patient's quality of life (4,5). This approach was based on
and outcomes, histological grade has been identified as a potentially more significant prognostic factor
[3,8,12].
Multiple studies have identified prognostic factors associated with survival, including age, tumor size,
surgical margins, mitotic index, bone or neurovascular invasion, histological subtype, p53
overexpression, and Ki-67 proliferation index [2,8].
In this specific case, TLE1 positivity and the absence of germline markers helped rule out recurrence of
the previous seminoma. Furthermore, the intermediate proliferation rate (Ki-67 ~20%) aligns with the
aggressive behavior observed on imaging and at surgery, consistent with reports from other series of
this neoplasm.
Treatment justification
Optimal management of these neoplasms requires a multidisciplinary approach at sarcoma referral
centers. Wide surgical resection with negative margins is the cornerstone of treatment and the most
important prognostic factor for survival [12]. Surgical resection may involve multivisceral resection or
resection with planned R1 margins when vascular or nerve structures are affected, provided that
neoadjuvant or adjuvant therapy is administered [2,13]. In the series by Yang et al. [2], en bloc resections
achieved prolonged local control without relapse, with follow-up ranging from 11 to 74 months.
Vertebral involvement remains a topic of discussion, as it includes tumors with borderline resectability.
According to NCCN and ESMO guidelines, histological grade, histological subtype, tumor size, and
involvement of vascular or nerve structures should be considered when deciding on neoadjuvant
management [1,2,11,13]. In our case, the multidisciplinary team determined that the patient met the
criteria for neoadjuvant chemotherapy with an MAI regimen and concurrent radiotherapy, aiming to
improve the likelihood of complete resection and locoregional control.
Preoperative radiotherapy may be considered in retroperitoneal sarcomas (STRASS trial), although its
benefit in specific SS is limited; however, it contributes to improved local control in high-grade tumors
or in cases with vertebral involvement [3, 4,13].
In our case, the patient received neoadjuvant chemotherapy and radiotherapy, and a wide multivisceral
local resection was performed, with planned positive margins (R1) on pathology, to preserve adjacent
structures, improve function, and maintain the patient's quality of life (4,5). This approach was based on
pág. 214
international and national consensus guidelines, such as the INC’s guidelines for managing
retroperitoneal sarcomas in patients with tumors in borderline resectability scenarios [13].
In the adjuvant setting, it is recommended for patients with microscopically positive margins or high-
grade subtypes, especially when neoadjuvant treatment was not administered, to help reduce the risk of
recurrence [2, 3,4,13].
Local recurrence after resection of retroperitoneal SS can reach up to 80%, and distant involvement in
25%, with pulmonary involvement being the most common, which directly affects oncological outcomes
[6,11].
Follow-up
Follow-up should be conducted at centers with extensive experience to evaluate early relapses and
provide interdisciplinary patient management. Surveillance is essential for detecting recurrences that
could potentially be curable. However, evidence on the most effective surveillance methods remains
limited [12,14].
It is recommended to perform MRI or CT scans of the tumor bed every 6 months during the first 2 to 3
years, then annually [11,14]. For patients undergoing major vertebral reconstructions, follow-up CT
scans should be performed every 6 months, along with regular neurological evaluations in collaboration
with the Neurosurgery service [14].
CONCLUSIONS
Primary retroperitoneal SS is a rare condition. Its diagnosis and treatment present a significant challenge
due to its location, aggressive behavior, and involvement of vascular and/or nerve structures. Imaging
studies such as CT and MRI are essential for characterization and surgical planning.
A multidisciplinary approach at referral centers is vital for optimizing resection and oncological
management, ensuring the treatment's oncological objectives are met. Retroperitoneal SS with vertebral
involvement is a rare and highly complex condition. This case demonstrates that multidisciplinary
management and careful surgical planning enable complete resection while preserving neurological
function, even in complex anatomical scenarios. We present the first reported case in Colombia and
Latin America of primary retroperitoneal SS with vertebral involvement, providing key clinical
information for the approach and management of future cases.
international and national consensus guidelines, such as the INC’s guidelines for managing
retroperitoneal sarcomas in patients with tumors in borderline resectability scenarios [13].
In the adjuvant setting, it is recommended for patients with microscopically positive margins or high-
grade subtypes, especially when neoadjuvant treatment was not administered, to help reduce the risk of
recurrence [2, 3,4,13].
Local recurrence after resection of retroperitoneal SS can reach up to 80%, and distant involvement in
25%, with pulmonary involvement being the most common, which directly affects oncological outcomes
[6,11].
Follow-up
Follow-up should be conducted at centers with extensive experience to evaluate early relapses and
provide interdisciplinary patient management. Surveillance is essential for detecting recurrences that
could potentially be curable. However, evidence on the most effective surveillance methods remains
limited [12,14].
It is recommended to perform MRI or CT scans of the tumor bed every 6 months during the first 2 to 3
years, then annually [11,14]. For patients undergoing major vertebral reconstructions, follow-up CT
scans should be performed every 6 months, along with regular neurological evaluations in collaboration
with the Neurosurgery service [14].
CONCLUSIONS
Primary retroperitoneal SS is a rare condition. Its diagnosis and treatment present a significant challenge
due to its location, aggressive behavior, and involvement of vascular and/or nerve structures. Imaging
studies such as CT and MRI are essential for characterization and surgical planning.
A multidisciplinary approach at referral centers is vital for optimizing resection and oncological
management, ensuring the treatment's oncological objectives are met. Retroperitoneal SS with vertebral
involvement is a rare and highly complex condition. This case demonstrates that multidisciplinary
management and careful surgical planning enable complete resection while preserving neurological
function, even in complex anatomical scenarios. We present the first reported case in Colombia and
Latin America of primary retroperitoneal SS with vertebral involvement, providing key clinical
information for the approach and management of future cases.
pág. 215
COMPLIANCE WITH ETHICAL STANDARDS
Informed consent: The study adhered to current international bioethical standards, such as the
Nuremberg Code, the Declaration of Helsinki, and the Belmont Report. It also complied with the
regulations set forth in Article 1502 of the Colombian Civil Code, Law 23 of 1981, Decree 3380 of
1981, and Resolution 008430 of 1993 of the Ministry of Health, which establish the scientific, technical,
and administrative standards for health research. Confidentiality was maintained in accordance with
Article 15 of the 1991 Political Constitution of Colombia. Furthermore, written informed consent was
obtained from the patient for the publication of the case and its corresponding images.
Conflicts of interest: The authors reported no conflicts of interest.
Use of Artificial Intelligence: The authors stated that they used artificial intelligence-assisted tools to
optimize writing style and clarity.
Funding sources: No external funding was received.
Authors’ contributions
- Study design and conception: Natalia Lasprilla, Erika Benito, Laura Arce Polanía, Emma Gómez,
Mauricio García.
- Data analysis and interpretation: Natalia Lasprilla, Erika Benito, Mauricio García, Sandra Díaz
- Manuscript writing: Natalia Lasprilla, Erika Benito, Laura Arce Polania
- Critical review: Natalia Lasprilla, Mauricio García, Sandra Díaz.
REFERENCES
1. Zhang G, Fang G, Meng M. Synovial sarcoma of the spinal canal and paraspinal muscle and
retroperitoneum: a case with extensive calcification. Childs Nerv Syst. 2021;37(12):3913–7.
doi:10.1007/s00381-021-05145-4
2. Yang M, Zhong N, Zhao C, et al. Surgical management and outcome of synovial sarcoma in the
spine. World J Surg Oncol. 2018;16(1):1–8. doi:10.1186/s12957-018-1471-x
3. Kim J, Lee S, Choi Y, Bae GE, Kim E, Eoh W. Synovial sarcoma of the spine: a case involving
paraspinal muscle with extensive calcification and surgical considerations. Eur Spine J. 2013;23(1):27–
32. doi:10.1007/s00586-013-3034-8
COMPLIANCE WITH ETHICAL STANDARDS
Informed consent: The study adhered to current international bioethical standards, such as the
Nuremberg Code, the Declaration of Helsinki, and the Belmont Report. It also complied with the
regulations set forth in Article 1502 of the Colombian Civil Code, Law 23 of 1981, Decree 3380 of
1981, and Resolution 008430 of 1993 of the Ministry of Health, which establish the scientific, technical,
and administrative standards for health research. Confidentiality was maintained in accordance with
Article 15 of the 1991 Political Constitution of Colombia. Furthermore, written informed consent was
obtained from the patient for the publication of the case and its corresponding images.
Conflicts of interest: The authors reported no conflicts of interest.
Use of Artificial Intelligence: The authors stated that they used artificial intelligence-assisted tools to
optimize writing style and clarity.
Funding sources: No external funding was received.
Authors’ contributions
- Study design and conception: Natalia Lasprilla, Erika Benito, Laura Arce Polanía, Emma Gómez,
Mauricio García.
- Data analysis and interpretation: Natalia Lasprilla, Erika Benito, Mauricio García, Sandra Díaz
- Manuscript writing: Natalia Lasprilla, Erika Benito, Laura Arce Polania
- Critical review: Natalia Lasprilla, Mauricio García, Sandra Díaz.
REFERENCES
1. Zhang G, Fang G, Meng M. Synovial sarcoma of the spinal canal and paraspinal muscle and
retroperitoneum: a case with extensive calcification. Childs Nerv Syst. 2021;37(12):3913–7.
doi:10.1007/s00381-021-05145-4
2. Yang M, Zhong N, Zhao C, et al. Surgical management and outcome of synovial sarcoma in the
spine. World J Surg Oncol. 2018;16(1):1–8. doi:10.1186/s12957-018-1471-x
3. Kim J, Lee S, Choi Y, Bae GE, Kim E, Eoh W. Synovial sarcoma of the spine: a case involving
paraspinal muscle with extensive calcification and surgical considerations. Eur Spine J. 2013;23(1):27–
32. doi:10.1007/s00586-013-3034-8
pág. 216
4. Kumar V, Abbas AK, Aster JC. Retroperitoneal Tumors. In: Fletcher CDM, Bridge JA,
Hogendoorn PCW, Mertens F, editors. WHO Classification of Tumours of Soft Tissue and Bone. 4th
ed. Lyon: IARC Press; 2013. p. 238–40.
5. Murphey MD, Gibson MS, Jennings BT, Crespo-Rodríguez AM, Fanburg-Smith J, Gajewski
DA. Imaging of synovial sarcoma: radiologic–pathologic correlation. Radiographics. 2006;26(5):1543–
65. doi:10.1148/rg.265065084
6. Tuan HX, Tuan TA, Tam N, et al. An infrequent case of retroperitoneal synovial
sarcoma. Radiol Case Rep. 2024;19(8):3456–60. doi:10.1016/j.radcr.2024.05.029
7. Bakri A, Shinagare AB, Krajewski KM, et al. Synovial sarcoma: imaging features of common
and uncommon primary sites, metastatic patterns, and treatment response. AJR Am J Roentgenol.
2012;199(2):W208–15. doi:10.2214/AJR.11.8039
8. Eilber FC, Brennan MF, Eilber FR, et al. Chemotherapy is associated with improved survival
in adult patients with primary extremity synovial sarcoma. Ann Surg. 2007;246(1):105–13.
doi:10.1097/01.sla.0000262787.88639.2b
9. Ulusan S, Kizilkilic O, Yildirim T, Hurcan C, Bal N, Nursal TZ. Radiological findings of
primary retroperitoneal synovial sarcoma. Br J Radiol. 2005;78(926):166–9. doi:10.1259/bjr/67990800
10. Pack GT, Tabah EJ. Primary retroperitoneal tumors: a study of 120 cases. Int Abstr Surg.
1954;99(3):209–231.
11. Choi JH, Ro JY. Retroperitoneal sarcomas: an update on the diagnostic pathology
approach. Diagnostics (Basel). 2020;10(9):642. doi:10.3390/diagnostics10090642
12. Gronchi A, Miah AB, Dei Tos AP, Abecassis N, Bajpai J, Bauer S, Biagini R, Bielack S, Blay
JY, Bolle S, Bonvalot S, Boukovinas I, Bovee JVMG, Boye K, Brennan B, Brodowicz T, Buonadonna
A, De Álava E, Del Muro XG, Dufresne A, Eriksson M, Fagioli F, Fedenko A, Ferraresi V, Ferrari A,
Frezza AM, Gasperoni S, Gelderblom H, Gouin F, Grignani G, Haas R, Hassan AB, Hecker-Nolting S,
Hindi N, Hohenberger P, Joensuu H, Jones RL, Jungels C, Jutte P, Kager L, Kasper B, Kawai A,
Kopeckova K, Krákorová DA, Le Cesne A, Le Grange F, Legius E, Leithner A, Lopez-Pousa A, Martin-
Broto J, Merimsky O, Messiou C, Mir O, Montemurro M, Morland B, Morosi C, Palmerini E, Pantaleo
MA, Piana R, Piperno-Neumann S, Reichardt P, Rutkowski P, Safwat AA, Sangalli C, Sbaraglia M,
4. Kumar V, Abbas AK, Aster JC. Retroperitoneal Tumors. In: Fletcher CDM, Bridge JA,
Hogendoorn PCW, Mertens F, editors. WHO Classification of Tumours of Soft Tissue and Bone. 4th
ed. Lyon: IARC Press; 2013. p. 238–40.
5. Murphey MD, Gibson MS, Jennings BT, Crespo-Rodríguez AM, Fanburg-Smith J, Gajewski
DA. Imaging of synovial sarcoma: radiologic–pathologic correlation. Radiographics. 2006;26(5):1543–
65. doi:10.1148/rg.265065084
6. Tuan HX, Tuan TA, Tam N, et al. An infrequent case of retroperitoneal synovial
sarcoma. Radiol Case Rep. 2024;19(8):3456–60. doi:10.1016/j.radcr.2024.05.029
7. Bakri A, Shinagare AB, Krajewski KM, et al. Synovial sarcoma: imaging features of common
and uncommon primary sites, metastatic patterns, and treatment response. AJR Am J Roentgenol.
2012;199(2):W208–15. doi:10.2214/AJR.11.8039
8. Eilber FC, Brennan MF, Eilber FR, et al. Chemotherapy is associated with improved survival
in adult patients with primary extremity synovial sarcoma. Ann Surg. 2007;246(1):105–13.
doi:10.1097/01.sla.0000262787.88639.2b
9. Ulusan S, Kizilkilic O, Yildirim T, Hurcan C, Bal N, Nursal TZ. Radiological findings of
primary retroperitoneal synovial sarcoma. Br J Radiol. 2005;78(926):166–9. doi:10.1259/bjr/67990800
10. Pack GT, Tabah EJ. Primary retroperitoneal tumors: a study of 120 cases. Int Abstr Surg.
1954;99(3):209–231.
11. Choi JH, Ro JY. Retroperitoneal sarcomas: an update on the diagnostic pathology
approach. Diagnostics (Basel). 2020;10(9):642. doi:10.3390/diagnostics10090642
12. Gronchi A, Miah AB, Dei Tos AP, Abecassis N, Bajpai J, Bauer S, Biagini R, Bielack S, Blay
JY, Bolle S, Bonvalot S, Boukovinas I, Bovee JVMG, Boye K, Brennan B, Brodowicz T, Buonadonna
A, De Álava E, Del Muro XG, Dufresne A, Eriksson M, Fagioli F, Fedenko A, Ferraresi V, Ferrari A,
Frezza AM, Gasperoni S, Gelderblom H, Gouin F, Grignani G, Haas R, Hassan AB, Hecker-Nolting S,
Hindi N, Hohenberger P, Joensuu H, Jones RL, Jungels C, Jutte P, Kager L, Kasper B, Kawai A,
Kopeckova K, Krákorová DA, Le Cesne A, Le Grange F, Legius E, Leithner A, Lopez-Pousa A, Martin-
Broto J, Merimsky O, Messiou C, Mir O, Montemurro M, Morland B, Morosi C, Palmerini E, Pantaleo
MA, Piana R, Piperno-Neumann S, Reichardt P, Rutkowski P, Safwat AA, Sangalli C, Sbaraglia M,
pág. 217
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13. Campillo-Pardo J, Zuluaga-Liberato A, Cuadrado-Franco D, et al. Indicaciones de radioterapia
y quimioterapia neoadyuvante y adyuvante en pacientes con sarcoma retroperitoneal: revisión no
sistemática de la literatura y abordaje terapéutico en el Instituto Nacional de Cancerología, Colombia.
Rev Colomb Cancerol. 2024;28(1):36-44. doi:10.35509/01239015.972.
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Oncology: Soft Tissue Sarcoma. Version 1.2025. NCCN; 2025
Scheipl S, Schöffski P, Sleijfer S, Strauss D, Strauss S, Sundby Hall K, Trama A, Unk M, van de Sande
MAJ, van der Graaf WTA, van Houdt WJ, Frebourg T, Casali PG, Stacchiotti S; ESMO Guidelines
Committee, EURACAN and GENTURIS. Soft tissue and visceral sarcomas: ESMO-EURACAN-
GENTURIS clinical practice guidelines for diagnosis, treatment and follow-up. Ann
Oncol. 2021;32(11):1348–1365. doi:10.1016/j.annonc.2021.07.006.
13. Campillo-Pardo J, Zuluaga-Liberato A, Cuadrado-Franco D, et al. Indicaciones de radioterapia
y quimioterapia neoadyuvante y adyuvante en pacientes con sarcoma retroperitoneal: revisión no
sistemática de la literatura y abordaje terapéutico en el Instituto Nacional de Cancerología, Colombia.
Rev Colomb Cancerol. 2024;28(1):36-44. doi:10.35509/01239015.972.
14. Von Mehren M, Kane JM, Armstrong SA, et al. NCCN Clinical Practice Guidelines in
Oncology: Soft Tissue Sarcoma. Version 1.2025. NCCN; 2025