EWSR1::WT1 Fusions in Neoplasms Other Than Conventional Desmoplastic Small Round Cell Tumor: Three Tumors Occurring Outside the Female Genital Tract.

Desmoplastic small round cell tumor (DSRCT) is a high-grade, primitive round cell sarcoma classically associated with prominent desmoplastic stroma, coexpression of keratin and desmin, and a characteristic EWSR1::WT1 gene fusion. DSRCT typically arises in the abdominopelvic cavity of young males with diffuse peritoneal spread and poor overall survival. Although originally considered to be pathognomonic for DSRCT, EWSR1::WT1 gene fusions have recently been detected in rare tumors lacking the characteristic morphologic and immunohistochemical features of DSRCT. Here, we report 3 additional cases of neoplasms other than conventional DSCRCT with EWSR1::WT1 gene fusions that occurred outside the female genital tract. Two occurred in the abdominopelvic cavities of a 27-year-old man and a 12-year-old girl, whereas the third arose in the axillary soft tissue of an 85-year-old man. All cases lacked prominent desmoplastic stroma and were instead solid and cystic with peripheral fibrous pseudocapsules and occasional intervening fibrous septa. Necrosis was either absent (1/3) or rare (2/3), and mitotic activity was low (<1 to 3 per 10 hpf). In immunohistochemical studies, there was expression of smooth muscle actin (3/3) and desmin (3/3), rare to focal reactivity for EMA (2/3), and variable expression of CK AE1/AE3 (1/3). Myogenin and MyoD1 were negative, and C-terminus-specific WT1 was positive in both cases tested (2/2). All 3 tumors followed a more indolent clinical course with 2 cases demonstrating no evidence of disease at 20 and 44 months after resection. The patient from case 3 died of other causes at 14 months with no evidence of recurrence. DNA methylation profiling showed that the 3 cases clustered with DSRCT; however, they demonstrated fewer copy number variations with 2 cases having a flat profile (0% copy number variation). Differential methylation analysis with hierarchical clustering further showed variation between the 3 cases and conventional DSRCT. Although further study is needed, our results, in addition to previous reports, suggest that EWSR1::WT1 gene fusions occur in rare and seemingly distinctive tumors other than conventional DSRCT with indolent behavior. Proper classification of these unusual soft tissue tumors with EWSR1::WT1 gene fusions requires direct correlation with tumor morphology and clinical behavior, which is essential to avoid overtreatment with aggressive chemotherapy.

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.

Response to chemotherapy combined with anlotinib plus anlotinib maintenance in intra-abdominal desmoplastic small round cell tumors (IADSRCT): a case report and literature review.

BACKGROUND: Intra-abdominal desmoplastic small round cell tumors (IADSRCT) are rare and aggressive neoplasia that are resistant to chemotherapy. Anlotinib is an oral multi-target tyrosine kinase inhibitor that also has anti-angiogenic and anti-proliferative properties. In this article, we report on a case showing effective and durable responses to chemotherapy combined with anlotinib in a young man with IADSRCT. CASE PRESENTATION: A 27-year-old man was admitted to our hospital complaining of a palpable periumbilical mass that had been present for longer than 4 months. The diagnosis of IADSRCT was confirmed by biopsy and immunohistochemistry. An extensive unresectable metastasis was found on the initial diagnosis. The patient received six cycles of chemotherapy combined with anlotinib, and maintenance therapy with anlotinib was recommended. Hematochezia, proteinuria and hypertension were observed, however, long-term maintenance therapy was well tolerated. A partial response was observed after two cycles of combined therapy and the patient was still alive with stable disease at the time of reporting. CONCLUSIONS: Chemotherapy combined with anlotinib plus anlotinib maintenance showed promising efficacy and manageable toxicity in the treatment of advanced IADSRCT.

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.

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.

Selective Immunoreactivity for WT1 Carboxy-Terminus Distinguishes Desmoplastic Small Round Cell Tumor From its Histologic Mimics.

Desmoplastic small round cell tumor (DSRCT) is an aggressive pediatric round cell sarcoma containing a characteristic EWSR1-WT1 gene fusion. In the absence of genetic data, distinguishing DSRCT from other small round cell tumors of childhood can be problematic due to overlapping histologic and immunohistochemical features. We studied the utility of immunohistochemistry with antibodies targeting both the amino-terminal and carboxy-terminal regions of the Wilms tumor-1 (WT1) protein in differentiating these groups of tumors. The study cohort included 33 cases of genetically confirmed pediatric round cell tumors (10 DSRCTs, 12 Wilms tumors, 10 Ewing sarcomas, and 1 CIC-rearranged sarcoma). Immunoreactivities and immunolocalization of both the WT1 amino-terminus and carboxy-terminus were scored and documented. All DSRCTs displayed selective reactivity for only the WT1 carboxy-terminus (10/10), while dual immunoreactivity for both the WT1 carboxy-terminus (12/12) and amino-terminus antibodies (12/12) were characteristic of Wilms tumors. CIC-rearranged sarcoma showed variable WT1 nuclear immunopositivity (1/1, 1/1) and Ewing sarcomas were consistently WT1-negative for both the WT1 amino-terminus (0/10) and carboxy-terminus (0/10). Dual WT1 amino-terminus and carboxy-terminus immunohistochemistry remains a helpful diagnostic tool in discriminating intraabdominal small round cell tumors, which serves as an adjunct to the genetic information in preventing misdiagnosis.

Beyond Wilms tumor: imaging findings and outcomes of rare renal tumors in children.

BACKGROUND: Compared to Wilms, non-Wilms renal tumors in children are less well understood due to their rare occurrence which limits precise definition of the typical imaging patterns. OBJECTIVE: This study aims to identify distinctive imaging findings, demographic characteristics and prognosis of pediatric non-Wilms renal tumors. MATERIALS AND METHODS: From January 2007 to December 2018, 207 patients with a diagnosis of primary kidney neoplasia were yielded from our radiology archive, 171 of whom were diagnosed with Wilms tumor, 4 with angiomyolipoma and one with nephrogenic rest. The remaining 31 patients with a diagnosis of primary kidney neoplasia were enrolled in this retrospective study. Imaging data, age, gender, prognosis and findings regarding follow-up were noted. RESULTS: Eight patients had renal cell carcinoma, seven had clear cell sarcoma, six had mesoblastic nephroma, four had rhabdoid tumor, three had desmoplastic small round cell tumor, two had cystic nephroma and one had metanephric stromal tumor. The age of diagnosis was > 8 years for renal cell carcinoma and desmoplastic small round cell tumor, < 5 years for rhabdoid tumor and < 7 months for mesoblastic nephroma. There was no gender preference for any tumor type. The prognosis for rhabdoid tumor was extremely poor in that all the patients followed up in our institute were deceased, whereas no recurrence was found in other tumors. Translocation type renal cell carcinoma had lower T2-weighted signal intensity, mesoblastic nephroma was a predominantly cystic mass, clear cell sarcoma was generally larger at presentation and extensive amorphous calcifications were seen in desmoplastic small round cell tumor. CONCLUSION: For the differential diagnosis of pediatric non-Wilms renal tumors, age is the most important factor, followed by propensity to metastasize/aggressive behavior of the mass. Knowledge of specific imaging findings of these tumors may help to narrow the differential diagnosis.

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.

Genomic and transcriptomic characterization of desmoplastic small round cell tumors.

Desmoplastic small round cell tumor (DSRCT) is a highly aggressive soft tissue tumor primarily affecting children and young adults. Most cases display a pathognomonic EWSR1-WT1 gene fusion, presumably constituting the primary driver event. Little is, however, known about secondary genetic changes that may affect tumor progression. We here studied 25 samples from 19 DSRCT patients using single nucleotide polymorphism arrays and found that all samples had copy number alterations. The most common imbalances were gain of chromosomes/chromosome arms 1/1q and 5/5p and loss of 6/6q and 16/16q, all occurring in at least eight of the patients. Five cases showed homozygous deletions, affecting a variety of known tumor suppressor genes, for example, CDKN2A and NF1. As almost all patients died of their disease, the impact of individual imbalances on survival could not be evaluated. Global gene expression analysis using mRNA sequencing on fresh-frozen samples from seven patients revealed a distinct transcriptomic profile, with enrichment of genes involved in neural differentiation. Two genes - GJB2 and GAL - that showed higher expression in DSRCT compared to control tumors could be further investigated for their potential as diagnostic markers at the protein level.

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.

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.

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.

NKX3.1 a useful marker for mesenchymal chondrosarcoma: An immunohistochemical study.

INTRODUCTION: Mesenchymal chondrosarcoma is a rare subtype of chondrosarcoma. The tumor has a characteristic bimorphic pattern with areas of poorly differentiated small round cell component and interspersed islands of well differentiated hyaline cartilage. Histological diagnosis of mesenchymal chondrosarcoma is very challenging especially in small biopsies when tumor presents with little cartilaginous component. In such cases, it is very difficult to distinguish mesenchymal chondrosarcoma from other round blue cell tumors like Ewing's sarcoma, rhabdomyosarcoma, small cell osteosarcoma and desmoplastic round blue cell tumor. Immunohistochemically, mesenchymal chondrosarcoma stains positive for NKX2.2, CD99, S100 and SOX9. This immunoprofile is non-specific and overlaps with other round blue cell tumors. Till recently, there was no reliable immunohistochemical marker to differentiate mesenchymal chondrosarcoma from other round blue cell tumors. NKX3.1, though widely used as a diagnostic biomarker for prostatic adenocarcinoma, has been recently proposed by Yoshida et al. (2020) as a unique marker of mesenchymal chondrosarcoma and EWSR1-NFATC2 sarcoma. OBJECTIVE: The aim of our study was to further explore utility of NKX3.1 as a diagnostic marker of mesenchymal chondrosarcoma. MATERIAL & METHODS: We applied NKX3.1 immunohistochemistry to 21 cases of mesenchymal chondrosarcoma and 32 cases of other round blue cell tumors. RESULTS: 14 out of 21 cases (66.7%) of mesenchymal chondrosarcoma stained positive for NKX3.1 with nuclear expression in small round component. Cartilaginous component was predominantly negative. All other round blue cell tumors showed negative results. CONCLUSION: Based on our study results we suggest that NKX3.1 is a useful immunohistochemical marker in differentiating mesenchymal chondrosarcoma from its histological mimics.

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.

Desmoplastic Small Round Cell Tumor in a Pregnant Woman: A Case Report and Literature Review.

Background: Desmoplastic small round cell tumor (DSRCT) is an aggressive malignant tumor commonly found in young men; most occurs in the abdominal cavity. Here we conducted an in-depth analysis of a pregnant patient in our hospital and explored all the case information in the literature on small round cell carcinoma of women. Case presentation: A 27-year-old pregnant woman underwent tumor resection in our hospital at 29 weeks gestational age for a large progressive shoulder lump. The postoperative pathology showed that the mass was a DSRCT. Genetic testing found no fusion gene. At 36 weeks gestation, a painful mass was found in the breast and proved to be a metastatic focus of the desmoplastic small round cell tumor. Twenty days after a successful cesarean section at 40 weeks gestation, she received the VAC-IE chemotherapy regimen, successfully completed the first course, but when awaiting the next chemotherapy, unfortunately, the patient died during follow-up due to tumor recurrence and metastasis. Conclusion: The treatment of DSRCT in pregnant women requires a multidisciplinary consultation, and the treatment and examination during pregnancy are subject to many constraints, which may have a negative impact on the patient's prognosis. Also, a review of the literature found that there is still no standard treatment protocol for DSRCT, and its prognosis in female patients is independent of age and tissue origin.

The Chicago Consensus on peritoneal surface malignancies: Management of desmoplastic small round cell tumor, breast, and gastrointestinal stromal tumors.

The Chicago Consensus Working Group provides multidisciplinary recommendations for the management of desmoplastic small round cell, breast, and gastrointestinal stromal tumors specifically related to peritoneal surface malignancy. These guidelines are developed with input from leading experts, including surgical oncologists, medical oncologists, pathologists, radiologists, palliative care physicians, and pharmacists. These guidelines recognize and address the emerging need for increased awareness in the appropriate management of peritoneal surface disease. They are not intended to replace the quest for higher levels of evidence.

Recurrent secondary genomic alterations in desmoplastic small round cell tumors.

BACKGROUND: Desmoplastic small round cell tumor (DSRCT) is a rare, highly aggressive, translocation-associated soft-tissue sarcoma that primarily affects children, adolescents, and young adults, with a striking male predominance. It is characterized by t(11;22) generating a novel EWSR1-WT1 fusion gene. Secondary genomic alterations are rarely described. METHODS: Tumor tissue from 83 DSRCT patients was assayed by hybrid-capture based comprehensive genomic profiling, FoundationOne® Heme next generation sequencing analysis of 406 genes and RNA sequencing of 265 genes. Tumor mutation burden was calculated from a minimum of 1.4 Mb sequenced DNA. Microsatellite instability status was determined by a novel algorithm analyzing 114 specific loci. RESULTS: Comprehensive genomic profiling identified several genomically-defined DSRCT subgroups. Recurrent genomic alterations were most frequently detected in FGFR4, ARID1A, TP53, MSH3, and MLL3 genes. With the exception of FGFR4, where the genomic alterations predicted activation, most of the alterations in the remaining genes predicted gene inactivation. No DSRCT were TMB or MSI high. CONCLUSIONS: In summary, recurrent secondary somatic alterations in FGFR4, ARID1A, TP53, MSH3, and MLL3 were detected in 82% of DSRCT, which is significantly greater than previously reported. These alterations may have both prognostic and therapeutic implications.

Desmoplastic Small Round Cell Tumor: Long-Term Complications After Cytoreduction and Hyperthermic Intraperitoneal Chemotherapy.

BACKGROUND: Desmoplastic small round cell tumor (DSRCT) is a rare intra-abdominal soft tissue sarcoma affecting adolescents and young adults. Cytoreduction, hyperthermic intraperitoneal chemotherapy (CRS/HIPEC), and adjuvant radiotherapy may improve local control. We review our experience with patients who undergo CRS/HIPEC and adjuvant radiotherapy for DSRCT. METHODS: A retrospective review was performed for patients with DSRCT from 2013 to 2017 who underwent CRS/HIPEC. Clinicopathologic, operative, and outcome data were reviewed. RESULTS: Ten CRS/HIPEC procedures were performed for nine patients (7 males, 6 Caucasian, median age 19 years (range 10-24)). Four patients presented with extra-abdominal disease; five had liver involvement. The median peritoneal cancer index was 16 (range 5-20). All received neoadjuvant chemotherapy. CCR 0/1 resection was possible in nine patients. Major complications occurred in four with no operative mortalities. All received adjuvant chemotherapy, seven received radiation therapy, and three received stem-cell transplant. All but one patient recurred after treatment. The median recurrence-free and overall survival (OS) were 12 and 45 months (95% confidence interval 35.1-54.9) respectively, with a 3-year OS of 55%. Long-term parenteral nutrition was required in eight for a median of 261 days (range 37-997). Clinically significant long-term complications requiring further surgery included gastroparesis (N = 1), small bowel obstruction (N = 3) and hemorrhagic cystitis (N = 2). CONCLUSIONS: Multimodal therapy for DSRCT consisting of multiagent neoadjuvant chemotherapy, CRS/HIPEC, adjuvant chemotherapy, and radiation therapy is associated with potential cumulative toxicity. Recurrence after resection is common. Prolonged parenteral nutrition may be necessary, and late gastrointestinal and genitourinary complications may require additional treatment.

The Chicago Consensus on Peritoneal Surface Malignancies: Management of Desmoplastic Small Round Cell Tumor, Breast, and Gastrointestinal Stromal Tumors.

The Chicago Consensus Working Group provides multidisciplinary recommendations for the management of desmoplastic small round cell tumor, breast, and gastrointestinal stromal tumor specifically related to peritoneal surface malignancy. These guidelines are developed with input from leading experts including surgical oncologists, medical oncologists, pathologists, radiologists, palliative care physicians, and pharmacists. These guidelines recognize and address the emerging need for increased awareness in the appropriate management of peritoneal surface disease. They are not intended to replace the quest for higher levels of evidence.

Desmoplastic Small Round Cell Tumor of the Kidney: Report of a Case, Literature Review, and Comprehensive Discussion of the Distinctive Morphologic, Immunohistochemical, and Molecular Features in the Differential Diagnosis of Small Round Cell Tumors Affecting the Kidney.

Desmoplastic small round cell tumor (DSRCT) is a rare, highly aggressive neoplasm typically presenting with widespread involvement of the abdominopelvic peritoneum of adolescent males, usually without organ-based primary. Although it is believed to originate from the serous (mainly peritoneal) membranes, intracranial, sinonasal, intraosseous, and other soft tissue sites are also documented. A chromosomal translocation t(11:22)(p13;q12) signature that fuses EWSR1 and WT1 genes results in the production of a chimeric protein with transcriptional regulatory activity that drives oncogenesis. Integration of clinical, morphologic, immunohistochemical, and genetic data is necessary to arrive at the correct diagnosis, especially when the tumor arises in an atypical site. A 15-year-old male presented with hematuria and was found to have a large renal tumor associated with adrenal, liver, lung, and bone metastases. Histopathologic and immunophenotypic features were distinctive for DSRCT. This diagnosis was confirmed by means of fluorescence in situ hybridization and cytogenetic analysis, which documented the pathognomonic t(11;22) translocation, and by reverse transcription polymerase chain reaction on snap-frozen tissue, which revealed the EWSR1/WT1-specific chimeric transcript. Despite high-dose chemotherapy and radiation therapy targeted to a single T11 vertebral metastasis, the disease progressed, and the patient died 4 years after the diagnosis. A search of electronic databases for DSRCT yielded 16 cases of well-documented renal primaries out of around 1570 cases from all sites gathered from the global literature. Desmoplastic small round blue cell tumor and other primary renal tumors considered in the differential diagnosis with DSRCT are discussed.