Desmoplastic small round cell tumor of the kidney: a case report and discussion.

A 13-year-old boy was admitted to the hospital with 1-month history of neck pain and a 2-week history of bilateral hip joint pain accompanied by low fever. Positron emission tomography-computed tomography (PET-CT) revealed the presence of a malignant tumor in the left kidney with metastases to the left renal hilum, retroperitoneum, para-aortic lymph nodes, and multiple bone sites throughout the body. Given that the patient's left kidney capsule was intact and the boundary with surrounding tissues was clear, left nephrectomy was performed. Postoperative pathological diagnosis showed desmoplastic small round cell tumor (DSRCT) of the left kidney. CAV-VIP alternating chemotherapy was given 20 days after the first stage surgery. After the end of the 6th cycle, the patient underwent surgery again. The tumor in front of the aorta and postcava, the greater omentum, the retroperitoneal lymph nodes and the hepatic hilum lymph nodes, and the visible tumors in the abdomen were removed. CAV-VIP alternating chemotherapy was continued after the second stage surgery. At the end of the 4th cycle of post operation chemotherapy, radiotherapy was started. An abdominal CT scan conducted 11 months after second-stage surgery did not reveal any recurrence of abdominal tumors; however bone metastases persisted. The patient is currently receiving oral targeted therapy with anlotinib while ongoing follow-up continues.

Desmoplastic Small Round Cell Tumor Presenting as an Intra/Extracranial Mass.

Desmoplastic small round cell tumors (DSRCTs) are highly malignant tumors, with distinct reciprocal chromosome translocation (11;22)(p13;q12). Intracranial metastasis is a very rare complication of this tumor, with only a few cases reported in the literature. To our knowledge, this is the only case presenting an extracranial extension of intracranial metastasis of DSRCT. A 33-year-old man was diagnosed with DSRCT in the pelvic cavity. He presented with a scalp lump and right-sided weakness. A biopsy showed metastasis from DSRCT. Metastatic DSRCT to the brain is extremely rare. Surgical resection followed by adjuvant treatment, including chemotherapy and radiation, is indicated as it has a poor prognosis. Moreover, aggressive treatment is warranted to prevent progression and relapse.

Desmoplastic small round cell tumor of bone revealed by 18F-FDG PET/CT: a case report with literature review.

A 50-year-old male presented with neck and shoulder pain. Chest CT and 18F-FDG PET/CT revealed osteolytic bone destruction in the left first rib and thoracic vertebrae with increased FDG uptake. Rib biopsy pathology indicated desmoplastic small round cell tumor (DSRCT).18F-FDG PET/CT can accurately locate the distribution of DSRCT and further guide the location of needle biopsy to assist the DSRCT.

Multifocal Desmoplastic Small Round Cell Tumor: A Case Report of a Rare Neoplasm.

Desmoplastic small round cell tumor (DSRCT) is a rare, highly aggressive malignancy predominantly affecting adolescents and young adults. We report a case of multifocal DSRCT in an 11-year-old male who presented with complaints of unilateral forehead swelling, proptosis, and ophthalmoplegia for four months along with abdominal pain and dysphagia for six months. A whole-body computed tomography revealed widespread lesions in the skull, orbit, thorax, and abdomen with local infiltration. Ultrasound-guided biopsy of the forehead lump was performed. Based on histopathological and immunohistochemical investigations, it was diagnosed to be a DSRCT with multifocal presentation. The patient underwent chemo-radiation but unfortunately succumbed to neutropenic sepsis and renal failure. DSRCT is a very rare, highly aggressive malignancy with an extremely poor prognosis. Orbital presentations are even rarer, with less than 10 such cases currently described in English medical literature.

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.

Enzalutamide Induces Cytotoxicity in Desmoplastic Small Round Cell Tumor Independent of the Androgen Receptor.

Desmoplastic Small Round Cell Tumor (DSRCT) is a rare, pediatric cancer caused by the EWSR1::WT1 fusion protein. DSRCT predominantly occurs in males, which comprise 80-90% of the patient population. While the reason for this male predominance remains unknown, one hypothesis is that the androgen receptor (AR) plays a critical role in DSRCT and elevated testosterone levels in males help drive tumor growth. Here, we demonstrate that AR is highly expressed in DSRCT relative to other fusion-driven sarcomas and that the AR antagonists enzalutamide and flutamide reduce DSRCT growth. However, despite these findings, which suggest an important role for AR in DSRCT, we show that DSRCT cell lines form xenografts in female mice at the same rate as male mice and AR depletion does not significantly alter DSRCT growth in vitro. Further, we find that AR antagonists reduce DSRCT growth in cells depleted of AR, establishing an AR-independent mechanism of action. These findings suggest that AR dependence is not the reason for male predominance in DSRCT and that AR-targeted therapies may provide therapeutic benefit primarily through an AR-independent mechanism that requires further elucidation.

Intra-Abdominal Desmoplastic Small Round Cell Tumor (DSRCT) and the Role of Hyperthermic Intraperitoneal Chemotherapy (HIPEC): A Review.

Desmoplastic small round cell tumor is a very rare and highly aggressive soft tissue sarcoma, usually presenting with multiple intra-abdominal tumors in young males. Patients present with advanced disease and the overall survival is dismal. Multiple studies report relatively favorable outcomes with multimodal treatment consisting of chemotherapy, surgery and radiotherapy. If resection is feasible, complete cytoreductive surgery is the cornerstone of surgical treatment. The benefit of hyperthermic intraperitoneal chemotherapy in addition to cytoreductive surgery is unclear, and few studies have evaluated this option. We sought to identify the role of hyperthermic intraperitoneal chemotherapy in patients with intra-abdominal desmoplastic small round cell tumor. Our review of the available literature revealed no clear survival benefit in performing hyperthermic intraperitoneal chemotherapy after cytoreductive surgery.

Highlighting the Diversity of Desmoplastic Small Round Cell Tumor: A Case Series.

Desmoplastic small round cell tumor (DSRCT) is a rare malignant tumor that occurs mainly in the retroperitoneum of children and young adults. In its prototypical form, DSCRT displays characteristic morphology with nested primitive small round cells in a desmoplastic stroma and a distinctive immunophenotype with polyphenotypic differentiation. However, DSCRT can also exhibit a broader clinical, histologic and immunohistochemical spectrum and, therefore, cause diagnostic difficulties. Given that DSCRT is an aggressive and nearly universally fatal disease, making the correct diagnosis is critically important. Herein, we report three patients with DSRCT and unusual clinical, morphologic or immunohistochemical characteristics, in order to highlight its remarkable diversity and increase awareness of this unusual, distinctive neoplasm.

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

Background: Desmoplastic small round cell tumor (DSRCT) is a rare, aggressive, mesenchymal malignancy of a separate clinicopathological entity. It has a predilection for young men, with no evidence of any ethnic predilection. The current diagnostic gold standard for DSRCT includes histopathologic, immunohistochemical, and cytogenetic studies in order to confirm the variable phenotypic expression and characteristic chromosomal translocation. Case summary: A 65-year-old man presented with a sensation of an abdominal mass and a presentation of an incomplete bowel obstruction. Initial lab tests were in the normal range except for carbohydrate antigen. Contrast-enhanced CT showed that a large, mass-confounding density was occupied in the omentum majus area of the middle and lower abdominal wall. A 3D reconstruction of the images was performed to clarify the relationship between the tumor and the colon and was confirmed by a colonoscopy. After surgery, immunohistochemistry and fluorescence in situ hybridization (FISH) revealed EWSR1-WT1 gene rearrangement at 22q12, confirming the diagnosis of desmoplastic small round cell tumor. Conclusion: Being different from the predilection of DSRCT for young men, the patient in our case is a 65-year-old man with a huge mass involving the transverse colon and the bladder.

Desmoplastic small round cell tumor cancer stem cell-like cells resist chemotherapy but remain dependent on the EWSR1-WT1 oncoprotein.

Desmoplastic Small Round Cell Tumor (DSRCT) is a rare and aggressive pediatric cancer driven by the EWSR1-WT1 fusion oncogene. Combinations of chemotherapy, radiation and surgery are not curative, and the 5-years survival rate is less than 25%. One potential explanation for refractoriness is the existence of a cancer stem cell (CSC) subpopulation able escape current treatment modalities. However, no study to-date has examined the role of CSCs in DSRCT or established in vitro culture conditions to model this subpopulation. In this study, we investigated the role of stemness markers in DSRCT survival and metastasis, finding that elevated levels of SOX2 and NANOG are associated with worse survival in sarcoma patients and are elevated in metastatic DSRCT tumors. We further develop the first in vitro DSRCT CSC model which forms tumorspheres, expresses increased levels of stemness markers (SOX2, NANOG, KLF4, and OCT4), and resists doxorubicin chemotherapy treatment. This model is an important addition to the DSRCT tool kit and will enable investigation of this critical DSRCT subpopulation. Despite lower sensitivity to chemotherapy, the DSRCT CSC model remained sensitive to knockdown of the EWSR1-WT1 fusion protein, suggesting that future therapies directed against this oncogenic driver have the potential to treat both DSRCT bulk tumor and CSCs.

Desmoplastic Small Round Cell Tumor of the Head and Neck: A Potential Diagnostic Pitfall.

Primary desmoplastic small round cell tumor (DSRCT) in the head and neck region is extremely rare. There is limited information about its clinicopathological characteristics, prognosis, and treatment modalities. The purpose of this study is to provide a comprehensive review of DSRCT occurring primarily in the head and neck, to demonstrate its peculiar morphology and immunohistochemical expression, and to address the differential diagnoses. A total of 25 cases were collected after a thorough review of the relevant literature. DSRCT was most frequently reported in the major salivary glands, followed by the eyes. Furthermore, some cases were misinterpreted as poorly differentiated carcinoma, Ewing sarcoma, and olfactory neuroblastoma. Diagnosing DSRCTs in the head and neck can be very challenging due to their rarity in this location, overlapping morphology, and immunohistochemistry. In these cases, following a systemic approach helps to solve diagnostic problems.

Advances in the treatment of pediatric solid tumors: A 50-year perspective.

In the United States, more than 10 000 cancers occur annually in children aged 0-14 years, and more than 5000 in adolescents aged 15-19. In the last 50 years, significant advances have been made in imaging, molecular pathology, stage and risk assessment, surgical approach, multidisciplinary treatment, and survival for pediatric solid tumors (particularly neuroblastoma, Wilms tumor, rhabdomyosarcoma, and hepatoblastoma). Moreover, the molecular driver for fibrolamellar hepatocellular carcinoma, which occurs in adolescence and young adulthood, has been identified.

Changing incidence and survival of desmoplastic small round cell tumor in the USA.

The incidence and prognosis of desmoplastic small round cell tumor (DSRCT) is inadequately understood. Survival analysis for DSRCT has not been investigated in a population-based study. We conducted a retrospective cohort study using the Surveillance, Epidemiology, and End Results (SEER) 9 Registry (1975-2018). Annual percent changes in incidence were estimated using SEER*Stat, and risk ratios were estimated using Poisson regression. Cox regression models were constructed to estimate the hazard ratio for survival at 5 years. The incidence rate of DSRCT has been rising in the last two decades. Men had a higher age-adjusted incidence rate, and nonmetropolitan counties had a higher incidence rate than metropolitan counties. Blacks had a higher risk of being diagnosed with DSRCT than whites. The observed survival at 12, 36, and 60 months was 81%, 39.9%, and 23.4%, respectively. Those >70 years had a poorer survival than those <60 years (P < 0.001). Compared to surgery with chemotherapy, surgery with chemoradiotherapy was linked to a 53% lower risk of mortality (P < 0.001). We conclude that the DSRCT incidence has been increasing since 2000 with a white male predominance. Gender doesn't affect survival in DSRCT, and surgery combined with chemoradiotherapy improves survival compared to surgical management with chemotherapy alone.

Novel patient-derived models of desmoplastic small round cell tumor confirm a targetable dependency on ERBB signaling.

Desmoplastic small round cell tumor (DSRCT) is characterized by the t(11;22)(p13;q12) translocation, which fuses the transcriptional regulatory domain of EWSR1 with the DNA-binding domain of WT1, resulting in the oncogenic EWSR1-WT1 fusion protein. The paucity of DSRCT disease models has hampered preclinical therapeutic studies on this aggressive cancer. Here, we developed preclinical disease models and mined DSRCT expression profiles to identify genetic vulnerabilities that could be leveraged for new therapies. We describe four DSRCT cell lines and one patient-derived xenograft model. Transcriptomic, proteomic and biochemical profiling showed evidence of activation of the ERBB pathway. Ectopic expression of EWSR1-WT1 resulted in upregulation of ERRB family ligands. Treatment of DSRCT cell lines with ERBB ligands resulted in activation of EGFR, ERBB2, ERK1/2 and AKT, and stimulation of cell growth. Antagonizing EGFR function with shRNAs, small-molecule inhibitors (afatinib, neratinib) or an anti-EGFR antibody (cetuximab) inhibited proliferation of DSRCT cells. Finally, treatment of mice bearing DSRCT xenografts with a combination of cetuximab and afatinib significantly reduced tumor growth. These data provide a rationale for evaluating EGFR antagonists in patients with DSRCT. This article has an associated First Person interview with the joint first authors of the paper.

Biodistribution and Radiation Dosimetry of Intraperitoneally Administered 124I-Omburtamab in Patients with Desmoplastic Small Round Cell Tumors.

The aim of this study was to assess the pharmacokinetics, biodistribution, and radiation dosimetry of 124I-omburtamab administered intraperitoneally in patients with desmoplastic small round cell tumor. Methods: Eligible patients diagnosed with desmoplastic small round cell tumor with peritoneal involvement were enrolled in a phase I trial of intraperitoneal radioimmunotherapy with 131I-omburtamab. After thyroid blockade and before radioimmunotherapy, patients received approximately 74 MBq of 124I-omburtamab intraperitoneally. Five serial PET/CT scans were obtained up to 144 h after injection. Multiple blood samples were obtained up to 120 h after injection. Organ-absorbed doses were calculated with OLINDA/EXM. Results: Thirty-one patients were studied. Blood pharmacokinetics exhibited a biphasic pattern consisting of an initial rising phase with a median half-time (±SD) of 23 ± 15 h and a subsequent falling phase with a median half-time of 56 ± 34 h. Peritoneal distribution was heterogeneous and diffuse in most patients. Self-dose to the peritoneal cavity was 0.58 ± 0.19 mGy/MBq. Systemic distribution and activity in major organs were low. The median absorbed doses were 0.72 ± 0.23 mGy/MBq for liver, 0.48 ± 0.17 mGy/MBq for spleen, and 0.57 ± 0.12 mGy/MBq for kidneys. The mean effective dose was 0.31 ± 0.10 mSv/MBq. Whole-body and peritoneal cavity biologic half-times were 45 ± 9 and 24 ± 5 h, respectively. Conclusion: PET/CT imaging with intraperitoneally administered 124I-omburtamab enables assessment of intraperitoneal distribution and estimation of absorbed dose to peritoneal space and normal organs before therapy.

Immunotherapy and Radioimmunotherapy for Desmoplastic Small Round Cell Tumor.

Desmoplastic small round cell tumor (DRSCT) is a highly aggressive primitive sarcoma that primarily affects adolescent and young adult males. The 5-year survival rate is 15-30% and few curative treatment options exist. Although there is no standard treatment for DSRCT, patients are most often treated with a combination of aggressive chemotherapy, radiation, and surgery. Targeted therapy inhibitors of PDGFA and IGF-1R, which are almost uniformly overexpressed in DSRCT, have largely failed in clinical trials. As in cancer in general, interest in immunotherapy to treat DSRCT has increased in recent years. To that end, several types of immunotherapy are now being tested clinically, including monoclonal antibodies, radionuclide-conjugated antibodies, chimeric antigen receptor T cells, checkpoint inhibitors, and bispecific antibodies (BsAbs). These types of therapies may be particularly useful in DSRCT, which is frequently characterized by widespread intraperitoneal implants, which are difficult to completely remove surgically and are the frequent cause of relapse. Successful treatment with immunotherapy or radioimmunotherapy following debulking surgery could eradiate these micrometasteses and prevent relapse. Although there has been limited success to date for immunotherapy in pediatric solid tumors, the significant improvements in survival seen in the treatment of other pediatric solid tumors, such as metastatic neuroblastoma and its CNS spread, suggest a potential of immunotherapy and specifically compartmental immunotherapy in DSRCT.

EWSR1-WT1 Target Genes and Therapeutic Options Identified in a Novel DSRCT In Vitro Model.

Desmoplastic small round cell tumor (DSRCT) is a rare and aggressive soft tissue sarcoma with a lack of effective treatment options and a poor prognosis. DSRCT is characterized by a chromosomal translocation, resulting in the EWSR1-WT1 gene fusion. The molecular mechanisms driving DSRCT are poorly understood, and a paucity of preclinical models hampers DSRCT research. Here, we establish a novel primary patient-derived DSRCT in vitro model, recapitulating the original tumor. We find that EWSR1-WT1 expression affects cell shape and cell survival, and we identify downstream target genes of the EWSR1-WT1 fusion. Additionally, this preclinical in vitro model allows for medium-throughput drug screening. We discover sensitivity to several drugs, including compounds targeting RTKs. MERTK, which has been described as a therapeutic target for several malignancies, correlates with EWSR1-WT1 expression. Inhibition of MERTK with the small-molecule inhibitor UNC2025 results in reduced proliferation of DSRCT cells in vitro, suggesting MERTK as a therapeutic target in DSRCT. This study underscores the usefulness of preclinical in vitro models for studying molecular mechanisms and potential therapeutic options.

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.

Desmoplastic small round cell tumor of the ovary: A rare but poor prognostic disease in a young woman!

Desmoplastic small round cell tumor (DSRCT) is a rare, aggressive neoplasm of uncertain histogenesis that preferentially involves the abdominal and pelvic cavities. DSRCT mainly develops in adolescent and young adults with a strong male predominance; the male to female ratio is 4:1. Ovarian location is exceptional. DSRCT generally develops in the abdomen and have a tendency towards peritoneal spread, with subsequent metastasis to distant lymph nodes, liver and lungs. It is a poorly understood malignancy with a very characteristic morphology, immunophenotype, cytogenetic features, and poor prognosis. This tumor can co-express epithelial, neuronal, and mesenchymal markers. Despite intensive therapy, including surgery, radiotherapy and chemotherapy, and immunotherapy; the 5-year survival is less than 15%.

Recurrent infantile inflammatory myofibroblastic tumor of mesentery--Case report and review of imaging findings.

Inflammatory myofibroblastic tumors (IMT) are rare soft tissue tumors of intermediate malignant potential with tendency for local recurrence. Although they can occur at all age groups, occurrence in infants is extremely unusual and their imaging characteristics are not well described. A 3-month-old female infant presented with gradually progressive abdominal distention without any fever or weight loss. She had a large ill-defined homogenous hypodense lesion of size 8.4 × 11.4 × 11.3 cm (APxTraxSag) in the abdomen showing mild delayed post contrast enhancement. She underwent exploratory laparotomy with gross total excision of mesenteric mass, histopathology of which was suggestive of IMT. She had recurrence within 6 months of complete resection with a well-defined heterogeneously enhancing lesion of size 1.8 × 1.8 × 2.3cm (APxTraxSag) in right paravesical region abutting the bladder without invasion with a similar lesion of size 4.4 × 2.1 × 3 cm (APxTraxSag) in left subdiaphragmatic region abutting superior surface of spleen (no invasion). Since, surgery in our patient would have entailed splenectomy and partial cystectomy, systemic therapy with ceritinib (anaplastic lymphoma kinase [ALK] inhibitor) was planned for her with which she had a near complete response after 2 months. A high index of suspicion is required to differentiate IMT from other common causes of mesenteric masses in children and role of radiologist is quintessential in this regard. Local recurrence with abutment but without invasion of surrounding structures points to the intermediate malignant pathology of IMT and may provide a clue to diagnosis. Systemic therapy is effective in patients who are ALK positive and destructive surgery should be avoided.