Abdominopelvic desmoplastic small round cell tumor with metastasis: A case report and literature review.

RATIONALE: Desmoplastic small round cell tumor (DSRCT) is a rare and rapidly metastasizing soft tissue sarcoma, distinguished by its unique cell morphology and pleomorphic differentiation. PATIENT CONCERNS: This report describes the case of an 18-year-old male diagnosed with abdominopelvic DSRCT exhibiting metastases to the peritoneum, liver, pleura, bone, and muscle. The patient primarily presented with symptoms of incomplete intestinal obstruction and an abdominal mass. DIAGNOSES: Colonoscopy revealed lumen stenosis caused by external compression mass. Contrast-enhanced computed tomography and 18F-fluorodeoxyglucose positron emission tomography/computed tomography revealed multiple lesions in the abdominopelvic cavity. A needle biopsy of an abdominal wall lesion established it as a malignant tumor, origin unknown. Immunohistochemical staining post-surgery showed positive results for Cytokeratin (CK), CK7, Desmin, Vimentin, Caudal type homeobox 2 (CDX2), and Ki-67. Fluorescence in situ hybridization analysis revealed an Ewing sarcoma breakpoint region 1/EWS RNA binding protein 1 (EWSR1) rearrangement, and next-generation sequencing identified an EWSR1-Wilms tumor protein 1 (WT1) gene fusion. INTERVENTIONS: The patient underwent laparoscopic exploratory surgery, which encompassed biopsy, ascites drainage, adhesion lysis, reinforcement of weakened sections of the small intestinal walls, and repositioning of twisted intestines. Postoperatively, the treatment protocol included fasting, rehydration, gastrointestinal decompression, and parenteral nutrition. However, the patient did not received chemotherapy. OUTCOMES: The patient declined further treatment and deceased in early November. LESSONS: This case highlights the nonspecific nature of DSRCT symptoms. In clinical practice, it is crucial to meticulously evaluate unexplained intestinal obstruction in young patients, considering DSRCT as a differential diagnosis to avoid delays in diagnosis.

Effective Treatment of Anlotinib Combined With Chemotherapy in Children With Desmoplastic Small Round Cell Tumor: A Case Series in a Single-center and Literature Review.

INTRODUCTION: Desmoplastic small round cell tumor (DSRCT) is a highly aggressive primitive sarcoma with a 5-year survival rate estimated at only 15% to 30%. Although few curative treatment options exist, patients are most often treated with a combination of aggressive chemotherapy, radiation, and surgery. Targeted therapy inhibitors of platelet-derived growth factor A, insulin-like growth factor receptor 1, and vascular endothelial growth factor receptor-2, which are almost uniformly overexpressed in DSRCT, have largely failed in clinical trials. Anlotinib is a multitarget receptor tyrosine kinase inhibitor that inhibits vascular endothelial growth factor receptor 1-3, fibroblast growth factor receptor 1-4, platelet-derived growth factor receptor α/ß, c-Kit, and Met. In this study, we presented 3 cases of DSRCT treated effectively with anlotinib combined with chemotherapy. CASE PRESENTATION: Three children DSRCT patients were enrolled from September 2020 to December 2021 and monitored until August 30, 2022. The clinical data were prospectively studied. The peritoneal cancer index classified all 3 patients as stage IV. After surgery, all 3 patients received anlotinib in combination with chemotherapy and reacted to the medication. For all 3 patients, clinical symptoms were substantially eased, and the size of the masses was reduced. Patient 1 and patient 3's progression-free survival had been extended, and anlotinib was continued as a maintenance medication in the 2 patients who were in good health at the end of the follow-up. Patient 2 died of postoperative complications 1 month after second-stage surgery. The main side effects of anlotinib were fatigue and hypertension. However, its toxicity was controllable and tolerable in children patients. CONCLUSIONS: This is the first report that anlotinib is effective in children with DSRCT. This report may provide an additional option for the treatment of metastatic DSRCT.

Desmoplastic small round cell tumor of the abdomen: A case report.

RATIONALE: Desmoplastic small round cell tumor (DSRCT) is a rare malignant tumor with poor prognosis, usually involving the peritoneum. There are currently no standardized treatment approaches. This study helped to further advance our understanding of DSRCT, and help to guide therapy. PATIENT CONCERNS: The patient, a 19-year-old male, presented with left-sided back pain with no obvious cause and occasional abdominal pain, and underwent abdominal electron computed tomography examination in our hospital suggesting consideration of small bowel mesenchymal tumor with possible multiple implantation metastasis in the abdominopelvic cavity. DIAGNOSES: After surgical treatment, the pathology report suggested a DSRCT, and immunohistochemistry and fluorescence in situ hybridization revealed EWSR1-WT1 gene rearrangement. Lung computer tomography and abdominal magnetic resonance imaging performed half a month later showed multiple solid nodules on the proximal septal surface of the right lung base, right posterior cardiac/right anterior inferior vena cava nodules, and multiple nodules in the abdominopelvic cavity, omenta, peritoneum, and around the liver or liver, all of which were considered as metastatic foci. INTERVENTIONS AND OUTCOMES: Patient received 5 cycles of chemotherapy after surgery. The review results showed a smaller size than before. Currently, he continues to receive treatment. LESSONS: The reported case has raised awareness of the importance of DSRCT in the treatment of chemotherapy, including its role in the differential diagnosis of abdominal tumors.

CXCR4-Directed Imaging and Endoradiotherapy in Desmoplastic Small Round Cell Tumors.

Desmoplastic small round cell tumor (DSRCT) is a rare, radiosensitive, yet difficult-to-treat sarcoma subtype affecting predominantly male adolescents. Extensive intraperitoneal seeding is common and requires multimodal management. With no standard therapy established, the prognosis remains poor, and new treatment options are needed. We demonstrate the clinical potential of C-X-C motif chemokine receptor 4 (CXCR4)-directed imaging and endoradiotherapy in DSRCT. Methods: Eight male patients underwent dual-tracer imaging with [18F]FDG and CXCR4-directed [68Ga]pentixafor PET/CT. A visual comparison of both tracers, along with uptake quantification in active DSRCT lesions, was performed. [68Ga]pentixafor uptake was correlated with immunohistochemical CXCR4 expression on tumor cells. Four patients with end-stage progressive disease underwent CXCR4-based endoradiotherapy. We report the safety, response by RECIST 1.1, and survival after endoradiotherapy. Results: Uptake of [68Ga]pentixafor in tumor lesions was demonstrated in all patients with DSRCT, providing diagnostic power comparable to [18F]FDG PET. Corresponding CXCR4 expression was confirmed by immunohistochemistry in all DSRCT biopsies. Finally, 4 patients were treated with CXCR4-directed [90Y]endoradiotherapy, 3 in a myeloablative dose range with subsequent autologous stem cell transplantation. All 3 required transfusions, and febrile neutropenia occurred in 2 patients (resulting in 1 death). Notably, severe nonhematologic adverse events were absent. We observed signs of response in all 3 patients, translating into disease stabilization in 2 patients for 143 and 176 d, respectively. In the third patient, postmortem autopsy confirmed a partial pathologic response. Conclusion: We validated CXCR4 as a diagnostic biomarker and a promising target for endoradiotherapy in DSRCT, demonstrated its feasibility, and provided the first evidence of its clinical efficacy.

Long-term survivors with desmoplastic small round cell tumor (DSRCT): Results from a retrospective single-institution case series analysis.

OBJECTIVE: To report on a retrospective study of primary DSRCT aiming at characterizing long-term survivors (LTS). METHODS: All consecutive patients treated at our institution for a primary DSRCT between 2000 and 2021 were retrospectively identified. Patients received multiagent chemotherapy ± surgery ± hyperthermic intraperitoneal chemotherapy (HIPEC) ± whole abdomino-pelvic radiotherapy (WAP-RT) ± high-dose chemotherapy ± maintenance chemotherapy (MC). Event-free survival (EFS) and overall survival (OS) were estimated by Kaplan-Meier method. Patients alive, without evidence of disease at ≥36 months from diagnosis, were defined as LTS. RESULTS: Thirty-eight patients were identified. All received multiagent chemotherapy; 27/38 (71%) surgery (7/27 [26%] plus HIPEC), 9/38 (24%) WAP-RT, 12/38 (32%) MC. At a median-follow-up of 37 months (IQR 18-63), overall median-EFS and median-OS were 15 and 37 months, respectively. All events occurred within 35 months. In patients who underwent surgery, median-EFS and median-OS were 19 and 37 months (23 and 43 months after R0/R1, and 10 and 19 months after R2 resection), respectively. LTS were 5/38 (13%), alive at 37, 39, 53, 64, 209 months. None had liver or extra-abdominal metastasis at diagnosis, they all received R0/R1 resection, 3/5 had WAP-RT, 2/5 MC, 1/5 received high-dose chemotherapy, none HIPEC. CONCLUSIONS: In our series cure was likely achieved in 13% of DSRCT. LTS had no liver/extra-abdominal disease, were treated with complete surgery, and possibly WAP-RT/MC.

Desmoplastic Small Round Cell Tumors With EWS-WT1 Transcript Expression: Should We Consider Children and Adult Patients Differently?

Desmoplastic small round cell tumor (DSRCT) is an aggressive sarcoma occurring in the young, teenager, and adult populations. The aim of this study is to compare initial tumor presentation, therapeutic management and scalability between pediatric and adult DSRCT patients and investigate the possibility of specific therapeutic approaches. A multicenter retrospective study of 81 Franco-Belgian medical files with DSRCT harboring Ewing sarcoma-Wilm tumor transcript was made. Median age was 17 years (3 to 58) with 42 children (13.5 y [3;17]) and 39 adults (28 y [18;58]). No significant differences were found between the 2 groups regarding initial symptoms and metastasis at diagnosis. The therapeutic approaches were similar for both groups: use of neoadjuvant chemotherapy (78.6% vs. 79.5%, P=1), primary surgery (71.4% vs. 69.2%, P=0.73), adjuvant chemotherapy (54.8% vs. 61.5%, P=0.99), radiotherapy (23.8% and 10.3%, P=0.11) and intraperitoneal chemotherapy (14.3% vs. 2.6%; P=0.11). Median time to recurrence was 12 versus 18 months (P=0.13). Overall survival at 2 years and recurrence free were 46.4% versus 60.1% (P=0.83) and 14.3% versus 16%, respectively (P=0.16). Clinical presentation, initial therapeutics and outcome of DSRCT are equivalent suggesting that similar management should be considered for children and adults with DSRCT.

Desmoplastic Small Round Cell Tumor of the Submandibular Gland: A Case Report and Literature Review.

Desmoplastic small round cell tumor (DSRCT) is a rare and aggressively malignant tumor mostly occurring in the abdominal and pelvic cavity of young patients. However, few cases had been reported concerning DSRCT occurring in the head and neck region. We presented a rare case of DSRCT of the right submandibular in a 25-year-old man. MRI revealed a 3 × 2-cm solid nodule located in the right submandibular, and physical examination showed no other occupying lesion elsewhere. Histologically, the tumor was composed of various-sized small round cell nests, embedded in an abundant desmoplastic stroma. Immunohistochemically, the tumor cells were typically positive for epithelial (CK and EMA), mesenchymal (vimentin and desmin), and neuroendocrine (CD56, NSE, Syn, and CgA) markers, but negative for WT1. Fluorescence in situ hybridization revealed the presence of a break apart involving the Ewing sarcoma (EWS) gene. The patient received chemotherapy and radiotherapy and relapsed after 19 months of follow-up. DSRCT of the submandibular gland is rare, and the diagnosis of this tumor in an uncommon location relies on the histomorphology, immunophenotype, and EWS gene translocation detection. Differential diagnosis including primary salivary gland tumors and the other small round cell tumors needs to be excluded.

Desmoplastic Small Round Cell Tumor With Ascending Intraspinal Metastasis at Recurrence: Case Report and Review of the Literature.

BACKGROUND: Desmoplastic small round cell tumor (DSRCT) is a rare and aggressive malignancy commonly involving the abdomen and/or pelvic peritoneum. Despite aggressive therapy, the prognosis remains poor. Central nervous system relapse is rare in abdominal/pelvic primary DSRCT. OBSERVATION: We report a case of a 10-year-old female with a large pelvic DSRCT and involvement of the rectosigmoid colon and liver. Following treatment with chemotherapy, and cytoreductive surgery with hyperthermic intraperitoneal chemotherapy an initial response was noted. With progressive lower limb weakness, recurrence with perineural invasion in the lumbosacral nerve root involving the conus was noted 2.5 years from diagnosis. Cerebrospinal fluid showed tumor cells with a molecular confirmation. CONCLUSIONS: Perineural invasion and ascending paralysis secondary to primary abdominal DSRCT has not been previously reported to our knowledge. We recommend a high index of suspicion for early and accurate diagnosis of this rare presentation.

A rare cause of bilateral pleural effusion - desmoplastic small round cell tumor.

Desmoplastic small round cell tumor (DSRCT) is a rare, extremely aggressive and malignant tumor predominantly affects young adolescent males and typically presents as a large intra-abdominal mass. However, tumor arising from other body sites are also reported in the literature. Histology and immunohistochemistry play an important role in the diagnosis and differentiating this rare tumor from other round cell tumors. A multidisciplinary approach consisting of a combination of surgery, chemotherapy and radiation therapy is the treatment of choice as there is no standard therapy.  We report a case of DSRCT of pleura presenting as bilateral pleural effusion in a young adolescent male who was treated with both surgery and chemotherapy. However, the patient succumbed to illness after one year of diagnosis.

Intraabdominal and ganglionic desmoplastic small round cell tumor: a case series.

INTRODUCTION: Desmoplastic small round cell tumor is a rare malignancy with poor prognosis, affecting young male patients. It frequently presents as a large abdominal mass with widespread peritoneal involvement at diagnosis. In late stages, metastases may be present. AIM: We retrospectively reviewed patient characteristics, presenting symptoms, tumor pathology, treatment, and outcome of four patients with desmoplastic small round cell tumor at our institution. CASES PRESENTATION: The first three cases reported are 32-, 17-, and 30-year-old North African males with intraabdominal desmoplastic small round cell tumor treated by surgery, chemotherapy, and radiation therapy with different follow-ups. The final case is a 16-year-old North African male with ganglionic desmoplastic small round cell tumor but no evidence of a tissue mass. He underwent two lines of chemotherapy with no response. The patient was lost after 2 years of follow-up. In all cases, desmoplastic small round cell tumor was confirmed by presence of t(11,22) (p13,q12) translocation. CONCLUSION: Treatment of desmoplastic small round cell tumor is based on multidisciplinary therapy. Despite high-dose chemotherapy, extensive surgical resection, and radiotherapy, desmoplastic small round cell tumor remains lethal.

Clinicopathological features of desmoplastic small round cell tumors: clinical series and literature review.

BACKGROUND AND PURPOSE: Desmoplastic small round cell tumor (DSRCT) is a highly malignant sarcoma that occurs in the abdominopelvic cavities of adolescents. The accurate diagnosis of DSRCT is challenging owing to limited literatures. Our study aimed to investigate the relationship between clinicopathological features and prognosis in patients with DSRCTs. METHODS: Data of 8 patients with DSRCT originating from the abdominal cavity were retrospectively reviewed. The clinical manifestations, pathological characteristics, treatment approaches, and prognosis were analyzed. The histopathological (identified using hematoxylin-eosin staining), immunohistochemical, and molecular diagnostic (using fluorescence in situ hybridization) features were also reviewed. RESULTS: All patients were male aged between 24 and 45 years (median age, 30 years). The main clinical symptoms included abdominal distension, abdominal pain, and constipation. Seven of the 8 patients developed metastases to either distant organs or lymph nodes. Multiple gray nodules with diameters of 1-10 cm and poorly defined boundaries were scattered throughout the omentum and mesentery. Histopathological examination demonstrated well-defined nests composed of small round blue cells separated by markedly desmoplastic stroma. Immunohistochemical analysis revealed positive expressions of desmin, vimentin and C-terminal of Wilm's tumor suppressor (WT-1). The Ewing sarcoma breakpoint region 1 gene fused with WT1 (EWSR1-WT1) gene fusion was detected in all patients. Cytoreductive surgery (CRS) was performed in 6 patients. Follow-up period ranged from 7.5 to 28.5 months with a median of 17.2 months. Three patients died during follow-up. CONCLUSION: DSRCT is highly aggressive and presents distinctive morphological features. CRS is the essential therapy for DSRCT. A test for the combined expression of desmin, cytokeratins, and C-terminal of WT-1, as well as the analysis of morphologic features, might be helpful during DSRCT diagnosis, and the EWSR1-WT1 gene fusion is the gold standard for definitive diagnosis. Our work will provide new insights into the diagnosis and treatment of DSRCTs.

Desmoplastic Small Round-cell Tumor: Retrospective Review of Institutional Data and Literature Review.

BACKGROUND: Desmoplastic small round-cell tumor (DSCRT) in adults is an extremely rare (age-adjusted incidence 0.3 per million) and aggressive sarcoma with limited data for optimal management. PATIENTS AND METHODS: Retrospective analysis of patients with DSCRT diagnosis (2010-2020) was performed following Institutional Review Board approval. The follow-up period was from pathological diagnosis to the last patient contact. Endpoints were type of response and duration of response. RESULTS: In the current analysis, first-line treatment in all cases was vincristine, anthracycline, and cyclophosphamide alternating with ifosfamide and etoposide (VAC-IE) with 100% response for a mean duration of 9.8 (range=5-12) months. Patients received 1-4 subsequent lines of therapy. All patients received temozolomide with irinotecan (50% partial response, duration 8-9 months). Two patients that underwent consolidative cytoreductive surgery with hyperthermic intraperitoneal chemotherapy had a longer survival (30.6 vs. 11.2 months). Patients suffered 100% mortality with a median survival was 17.8 (range=11.2-30.6) months. CONCLUSION: While aggressive multimodality treatment is always warranted for DSCRT, the options are limited by the multicentric presentation, short-lived initial response and lack of established subsequent therapy portending a poor prognosis. Consolidative cytoreductive surgery following first-line therapy may improve survival.

Desmoplastic Small Round Cell Tumors: A review with focus on clinical management and therapeutic options.

Desmoplastic Small Round Cell Tumors (DSRCTs) are an entity of rare, aggressive soft tissue sarcomas described by Gerald and Rosai in 1989. It predominantly affects male adolescents and young adults, with a peak incidence between an age of 20 and 30 years. Typically, DSRCT demonstrate as multiple small tumor nodules within the abdominal cave, retroperitoneum and pelvis. In more than 50% of the cases, the neoplasm presents metastatic at the timepoint of diagnosis. Histologically, DSRCTs have a characteristic morphology with sharply demarcated islands of uniform small round cells in abundant desmoplastic stroma organized in loose extracellular matrix. Immunohistochemistry reveals a polyphenotypic differentiation with co-expression of epithelial, myogenic, mesenchymal and neural markers. The morphology is highly variable and can hinder diagnosis. The most consistent molecular characteristic of DSRCT is the reciprocal t(11;22)(p13q12) translocation. This mutation leads to a formation of the EWSR1-WT1 fusion oncogene, which encodes for a chimeric protein with transcriptional regulatory activity and is regarded as driving source of the disease. To date, there is no standardized concept for clinical management, staging and treatment. Patients receive an aggressive multimodal therapeutic approach consisting of chemotherapy, radical surgical procedures, hyperthermic, intraperitoneal chemotherapy (HIPEC) and radiation. New targeted therapies are used in experimental settings as salvage therapy. So far, none of these therapies showed significant long-term success. This review gives an overview of diagnostic difficulties and pitfalls, discusses therapeutic strategies and highlights options for clinical management.

Hyperthermic intraperitoneal chemotherapy (HIPEC) as another treatment modality for desmoplastic round cell tumour patients: first paediatric experience from UK.

We present the first young paediatric patient with desmoplastic small round cell tumour (DSRCT) treated in UK with hyperthermic intraperitoneal chemotherapy (HIPEC). A 7-year-old girl was diagnosed with abdominal DSRCT with peritoneal and liver metastases. After six cycles of chemotherapy she obtained a partial response, including almost complete resolution of the two liver metastases. It was decided to pursue cytoreductive surgery (CRS) combined with HIPEC, a procedure commonly performed in adults, but seldom in a child. The surgery was macroscopically complete and the HIPEC uncomplicated. She continued treatment without delays, including whole abdomino-pelvic radiotherapy and maintenance chemotherapy (cyclophosphamide/vinorelbine for 12 months). She is currently in complete remission 4 months after end of treatment and 26 months after diagnosis. HIPEC was made possible by successful collaboration between multiple teams. CRS-HIPEC proved to be safe and feasible and could be offered to other children with diagnoses of peritoneal malignancies across the UK.

Sclerosing Encapsulating Peritonitis in a Pediatric Patient Treated With Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy.

BACKGROUND: Sclerosing encapsulating peritonitis (SEP) is a rare chronic inflammatory condition characterized by small bowel encapsulation by a thick fibrocollagenous membrane. Patients with SEP often present with nonspecific symptoms, such as abdominal pain and distension, however some patients may present with symptoms suggestive of intestinal obstruction. Secondary SEP has been reported in patients undergoing peritoneal dialysis and has been recently described in adults following cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). OBSERVATIONS: We report a clinical case of a 13-year-old female who presented with worsening abdominal pain and distension and persistent emesis who was found to have SEP 13 months following CRS and HIPEC for management of desmoplastic small round cell tumor and subsequently required operative intervention. CONCLUSION: Although there have been published reports of adult patients experiencing cases of SEP following CRS/HIPEC, this is the first published case of secondary SEP occurring in a pediatric oncology patient.

Multimodal Therapy Including Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy Can Result in Long-term Disease-free Survival in Pediatric Desmoplastic Small Round Cell Tumor With Extraperitoneal Disease.

Desmoplastic small round cell tumor is a rare sarcoma with 5-year overall survival of 15%. An 8-year-old female presented with diffuse abdominal/pelvic desmoplastic small round cell tumor including numerous liver metastasis. She underwent neoadjuvant chemotherapy followed by cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Residual disease was found shortly after CRS/HIPEC which was resected, followed by whole abdomen/pelvic radiation and autologous hematopoietic cell transplant. Previous papers have reported dismal survival in patients with liver metastasis and residual disease arguing against CRS/HIPEC. Our patient remains disease-free over 6 years after completing therapy indicating long-term survival is achievable with aggressive multimodal therapy.

Mediastinal desmoplastic small round cell tumor.

RATIONALE: Desmoplastic small round cell tumor (DSRCT) is a rare distinct tumor with a high-grade malignancy. PATIENT CONCERNS: A 51-year-old male visited a local hospital in April 2016 complaining of shortness of breath, chest tightness and pain, and exhibited significant swelling in both sides of the chest. DIAGNOSES: CT demonstrated thoracic symmetry and no abnormalities were observed in the soft tissues of the ribs and the chest wall. A general observation of CT-guided puncture biopsy revealed 2 stripes of gray and grayish-white puncture tissues of 0.5 and 1 cm in length, respectively, and 0.1 cm in diameter. These results preliminarily suggested a (mediastinum) malignant small round cell tumor. INTERVENTION: Given the progression of the disease, the chemotherapy regimen, consisting of ifosfamide and etoposide, was altered during the course and radiotherapy (total of 70 Gy of mediastinal Y field radiation) was conducted. OUTCOMES: The patient and his family declined further treatment. Through follow-up, the total survival period was determined as 17 months. LESSONS: DSRCT is a rare interstitial malignant tumor. Effective cytoreduction combined with comprehensive therapies could achieve partial remission or prolong the survival of patients.

Small Round Blue Cell Sarcoma Other Than Ewing Sarcoma: What Should an Oncologist Know?

OPINION STATEMENT: The diagnosis of round cell sarcomas has changed rapidly over the last decade, causing much diagnostic confusion for pathologists and oncologists. The advances in diagnosis are largely due to the advent of next-generation sequencing techniques, which allowed the recognition of novel gene fusions in round cell sarcomas. The new 5th edition of the WHO Classification of Tumors of Soft Tissue and Bone recognizes four subgroups of undifferentiated round cell sarcomas: Ewing sarcoma, CIC-rearranged sarcomas, BCOR-altered sarcomas, and sarcomas with EWSR1-non-ETS fusions, in addition to desmoplastic small round cell tumor. This classification is based on a variety of publications showing that each of these molecular subtypes has unique clinical and prognostic characteristics distinct from Ewing sarcoma, therefore supporting the validity of recognizing these as discrete diagnostic entities. Despite our improved ability to diagnose these new round cell sarcomas, there remains confusion on how best to identify and treat these tumors. However, several key clinicopathologic features can point the physician toward the correct diagnosis. The goal of the following article is to emphasize the key clinical, pathologic, molecular, and prognostic differences between Ewing sarcoma and these non-Ewing round cell malignancies to improve recognition of these rare diseases.

Tumor desmoplásico de célula pequeña y redonda paratesticular/testicular: reporte de caso y revisión de la literatura / Paratesticular/testicular desmoplastic round small cell malignant tumor: case report and literature review

Resumen El tumor desmoplásico de célula redonda y pequeña (TDCRP) es una patología neoplásica maligna agresiva y poco común. Afecta predominantemente a hombres entre la segunda y tercera década de la vida. Los pacientes que la padecen tienen un pronóstico pobre, con una supervivencia global a 5 años de hasta el 30%. Por lo general se presenta como una masa en la cavidad abdominal, frecuentemente multifocal. Para su tratamiento se recomienda un enfoque multimodal con cirugía, quimioterapia y radioterapia. Poco más de 20 casos de TDCRP a nivel testicular/paratesticular se han reportado en la literatura. A continuación, se presenta un caso ilustrativo en esta localización, se discute el caso y se realiza revisión de la literatura.

Abstract Desmoplastic small round cell tumor (DSRCT) is an aggressive and rare malignant neoplasm. It mainly affects young men in their twenties and thirties. Patients with it have a poor prognosis, with a 5-year survival rate of up to 30%. It generally presents as a mass in the abdominal cavity, often multifocal. A multimodal approach is recommended for its treatment, with surgery, chemotherapy, and radiotherapy. Just over 20 cases of testicular/paratesticular DSRCT have been reported in the literature. Below, we present an illustrative case in this location, we discuss the case and review the literature.