CT, MRI, and FDG-PET/CT imaging findings of abdominopelvic desmoplastic small round cell tumors: correlation with histopathologic findings

Multiple Desmoplastic Small Round Cell Tumor in the Intestine: A Case Report

INTRODUCTION

Desmoplastic small round cell tumor (DSRCT) is a highly malignant sarcoma and an extremely rare tumor, predominantly found in the abdominal and pelvic regions. Here, we report the case of a patient who underwent surgical treatment for multiple desmoplastic round cell tumor in the intestine.

CASE PRESENTATION

A 38-year-old male patient visited our hospital after a health check revealed positive occult blood in his stool and a colonoscopy revealed tumors in descending colon and sigmoid colon. Biopsy results revealed poorly differentiated adenocarcinoma. Chest and abdominal enhanced computed tomography revealed 3 tumors from descending colon to sigmoid colon and numerous peritoneal disseminations. Based on these findings, we diagnosed multiple colon cancers and performed a laparoscopic left hemicolectomy. Hematoxylin-Eosin (H&E) staining showed that in all tumors, atypical cells with large and small swollen nuclei formed irregular solid nests of various sizes against a background of extensive desmoplastic or myxomatous stroma. Immunohistochemistry showed that tumor cells were AE1/3 (+), S-100 (-), Desmin (-), WT1 (-). Genetic analysis detected the Ewing's sarcoma and Wilms tumor fusion gene at another inspection agency. Histopathological examination identified desmoplastic small round cell tumor. The patient was discharged on the 19th postoperative day without postoperative complications. He will undergo chemotherapy at another hospital.

CONCLUSIONS

We experienced a very rare case of DSRCT. DSRCT is a fatal disease that primarily affects adolescent and young adult males. Currently, there is no proven treatment. More case reports are essential to improve management of this disease.

Desmoplastic Small Round Cell Tumor: a study of CT, MRI, PET/CT multimodal imaging features and their correlations with pathology

PURPOSE

Exploring the computed tomography (CT), magnetic resonance imaging (MRI), and fluorodeoxyglucose positron emission tomography (FDG-PET)/CT Multimodal Imaging Characteristics of Desmoplastic Small Round Cell Tumor (DSRCT) to enhance the diagnostic proficiency of this condition.

METHODS

A retrospective analysis was performed on clinical data and multimodal imaging manifestations (CT, MRI, FDG-PET/CT) of eight cases of DSRCT. These findings were systematically compared with pathological results to succinctly summarize imaging features and elucidate their associations with both clinical and pathological characteristics.

RESULTS

All eight cases within this cohort exhibited abdominal-pelvic masses, comprising six solitary masses and two instances of multiple nodules, except for one case located in the left kidney, the remaining cases lacked a clear organ source. On plain images, seven cases exhibited patchy areas of low density within the masses, four cases showed calcification within the masses. Post-contrast imaging displayed mild-to-moderate, uneven enhancement. Larger masses displayed patchy areas without significant enhancement at the center. In the four MRI examinations, T1-weighted images exhibited uneven, low signal intensity, while T2-weighted images demonstrated uneven high signal intensity. Imaging unveiled four cases of liver metastasis, four cases of ascites, seven cases of lymph node metastasis, three cases of diffuse peritoneal thickening, and one case involving left ureter invasion with obstruction. In the FDG-PET/CT examinations of seven cases, multiple abnormal FDG accumulations were observed in the abdominal cavity, retroperitoneum, pelvis, and liver. One postoperative case revealed a new metastatic focus near the colonic hepatic region. The range of maximum standardized uptake values (SUVmax) for all lesions are 6.62-11.15.

CONCLUSIONS

DSRCT is commonly seen in young men, and the imaging results are mostly multiple lesions with no clear organ source. Other common findings include intratumoral calcification, liver metastasis, ascites, peritoneal metastasis, and retroperitoneal lymph node enlargement. The combined use of CT, MRI and FDG-PET/CT can improve the diagnostic accuracy and treatment evaluation of DSRCT. However, it is imperative to underscore that the definitive diagnosis remains contingent upon pathological examination.

Role and Efficacy of 18F-FDG PET/CT in Following Up Desmoplastic Small Round Cell Tumor of the Abdomen: A Case Report

Desmoplastic small round cell tumor (DSRCT) is an exceptionally rare and highly aggressive primary peritoneal neoplasm predominantly seen in adolescents and young adults. Despite the availability of various treatment modalities, the prognosis remains grim due to the tumor's aggressive nature and tendency for widespread metastasis. Although imaging of DSRCT is frequently documented using computed tomography (CT), the role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in the initial diagnosis, staging, and particularly in the follow-up evaluation, is less explored. This case report details the role and efficacy of 18F-FDG PET/CT in the follow-up of a patient with extensive peritoneal involvement by DSRCT, demonstrating its added advantage in monitoring treatment response over conventional CT imaging.

Imaging Diagnosis of Desmoplastic Small Round Cell Tumor: A Report of Two Cases

Desmoplastic small round cell tumor (DSRCT) is a rare multifocal peritoneal sarcoma, typically found in adolescent and young adult males. Symptoms are nonspecific and vary depending on tumor involvement. Diagnosis is primarily histopathological, although imaging results can assist in the diagnostic process. Although not pathognomonic, certain radiologic findings can help narrow down potential diagnoses and sometimes suggest the condition, as seen in our cases. Treatment options are not well-established or effective, and despite employing various therapeutic approaches, the prognosis remains poor. We present two cases of boys aged 11 and 10 with a final diagnosis of DSRCT, emphasizing the imaging findings.

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.

Update of pediatric soft tissue tumors with review of conventional MRI appearance-part 2: vascular lesions, fibrohistiocytic tumors, muscle tumors, peripheral nerve sheath tumors, tumors of uncertain differentiation, and undifferentiated small round cell sarcomas

There are numerous soft tissue tumors and tumor-like conditions in the pediatric population. Magnetic resonance imaging is the most useful modality for imaging these lesions. Although certain soft tissue lesions exhibit magnetic resonance features characteristic of a specific diagnosis, most lesions are indeterminate, and a biopsy is necessary for diagnosis. We provide a detailed update of soft tissue tumors and tumor-like conditions that occur in the pediatric population, emphasizing each lesion's conventional magnetic resonance imaging appearance, using the recently released 5^th edition of the World Health Organization Classification of Soft Tissue and Bone Tumors as a guide. In part one of this review, pediatric tumor-like lesions, adipocytic tumors, fibroblastic and myofibroblastic tumors, and perivascular tumors are discussed. In part two, vascular lesions, fibrohistiocytic tumors, muscle tumors, peripheral nerve sheath tumors, tumors of uncertain differentiation, and undifferentiated small round cell sarcomas are reviewed. Per the convention of the WHO, these lesions involve the connective, subcutaneous, and other non-parenchymatous organ soft tissues, as well as the peripheral and autonomic nervous system.

Peritoneal disease: key imaging findings that help in the differential diagnosis

The peritoneum is a unique serosal membrane, which can be the site of primary tumors and, more commonly, secondary pathologic processes. Peritoneal carcinomatosis is the most common malignant condition to affect the peritoneal cavity, and the radiologist plays an important role in making the diagnosis and assessing the extent of disease, especially in sites that may hinder surgery. In this review, we address the role of the radiologist in the setting of peritoneal pathology, focusing on peritoneal carcinomatosis as this is the predominant malignant process, followed by revising typical imaging findings that can guide the differential diagnosis.We review the most frequent primary and secondary peritoneal tumor and tumor-like lesions, proposing a systemic approach based on clinical history and morphological appearance, namely distinguishing predominantly cystic from solid lesions, both solitary and multiple.

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.

Intra-Abdominal Desmoplastic Small Round Cell Tumor: Current Treatment Options and Perspectives

Intra-abdominal desmoplastic small round cell tumor (IDSRCT) is a rare and highly malignant soft tissue neoplasm, which is characterized by rapid progression and poor prognosis. The mechanism underlying the development of this neoplasm remains elusive, but all cases are characterized by the chromosomal translocation t (11;22) (p13; q12), which results in a formation of EWSR1-WT1 gene fusion. The diagnosis of IDSRCT is often made with core-needle tissue biopsy specimens or laparoscopy or laparotomy. Immunohistochemical analyses have shown the co-expression of epithelial, neuronal, myogenic, and mesenchymal differentiation markers. FISH or reverse transcription polymerase chain reaction detecting EWS-WT1 fusion can be performed to assist in molecular confirmation. There is no standard of care for patients with IDSRCT currently, and majority of newly diagnosed patients received the aggressive therapy, which includes >90% resection of surgical debulking, high-dose alkylator-based chemotherapy, and radiotherapy. More recently, targeted therapy has been increasingly administered to recurrent IDSRCT patients and has been associated with improved survival in clinical conditions. Immunotherapy as a possible therapeutic strategy is being explored in patients with IDSRCT. In this review, we summarize currently available knowledge regarding the epidemiology, potential mechanisms, clinical manifestations, diagnosis, treatment, and prognosis of IDSRCT to assist oncologists in comprehensively recognizing and accurately treating this malignancy.

Desmoplastic Small Round Cell Tumor: A Review of Main Molecular Abnormalities and Emerging Therapy

Simple Summary

Desmoplastic small round cell tumor is a rare neoplasm with extremely aggressive behavior. Despite the multimodal treatment for newly diagnosed patients with chemotherapy, cytoreductive surgery and radiation, the cure rate is still low. For relapsed or progressive disease, there is limited data regarding second and third-line therapies. Novel agents have shown only modest activity. Recent molecular changes have been identified in this disease and this opens opportunities to be explored in future clinical trials.

Abstract

Desmoplastic small round cell tumor (DSRCT) is an extremely rare, aggressive sarcoma affecting adolescents and young adults with male predominance. Generally, it originates from the serosal surface of the abdominal cavity. The hallmark characteristic of DSRCT is the EWSR1–WT1 gene fusion. This translocation up-regulates the expression of PDGFRα, VEGF and other proteins related to tumor and vascular cell proliferation. Current management of DSRCT includes a combination of chemotherapy, radiation and aggressive cytoreductive surgery plus intra-peritoneal hyperthermic chemotherapy (HIPEC). Despite advances in multimodal therapy, outcomes remain poor since the majority of patients present disease recurrence and die within three years. The dismal survival makes DSRCT an orphan disease with an urgent need for new drugs. The treatment of advanced and recurrent disease with tyrosine kinase inhibitors, such as pazopanib, sunitinib, and mTOR inhibitors was evaluated by small trials. Recent studies using comprehensive molecular profiling of DSRCT identified potential therapeutic targets. In this review, we aim to describe the current studies conducted to better understand DSRCT biology and to explore the new therapeutic strategies under investigation in preclinical models and in early phase clinical trials.

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 tumour in the Afro-Caribbean population: case report with imaging findings

Desmoplastic Small Round Cell Tumour (DSRCT) is a rare malignancy that has only a few cases documented in the literature. We report a case of DSRCT in the abdomen and pelvis that was identified following ultrasound-guided biopsy of one of the numerous liver lesions seen on imaging in a 13-year-old Afro-Caribbean female with increased abdominal girth. The tumour was characterized by all routine imaging modalities available at the time. To our knowledge, this is the first reported and published case in the English speaking Caribbean. In the review of the literature, we correlate the imaging findings with previously reported cases. The diagnosis of DSRCT cannot be made solely using standard imaging techniques, but radiologists should be suspicious of DSRCT as a differential diagnosis in a young patient with increased abdominal girth, multiple liver and peritoneal deposits seen on imaging. Written informed consent for the case to be published (incl. images, case history, and data) was obtained from the parents of this patient for publication of this case report, including accompanying images.

Primary desmoplastic small round cell tumor of the tibia: PET/CT and MRI presentation of a rare case and review of the literature

Desmoplastic small round cell tumor (DSRCT) was a soft tissue sarcoma of mesenchymal cell origin that typically exhibited a multi-phenotypic pattern of immunohistochemical staining. DSRCT mainly presented in the abdomen sites and primary occurrence in bone was exceptional. In this study, we reported a new case of primary DSRCT of the tibia in a 33-year-old man who had intermittent pain in the left tibia. Radiographs showed transparent lesions in the left upper tibial. MRI revealed a lobular, lytic and ill-identified lesion with adjacent soft tissues swelling of the upper left tibia. CT confirmed notable destruction and wormlike osteolysis of the bone cortex. PET/CT showed a mass of high uptakes, indicating the malignance. He accepted surgical resection with followed multi-agent chemotherapy, containing vincristine, doxorubicin, ifosfamide and etoposide. Clinically and radiologically, the patient did not show any evidence of recurrence or metastasis at 30 months after surgical treatment. Primary osteogenic DSRCT was extremely rare and should be considered in differential diagnosis of bone tumors.

Primary desmoplastic small-round-cell tumor of the ovary

BACKGROUND

Desmoplastic small-round-cell tumor (DSRCT) is an extremely rare and highly aggressive malignancy. It is of yet unclear origin, but it is assumed to be of a mesothelial origin based on its tendency for widespread metastasis in serosal linings.

CASE PRESENTATION

In this report, we describe a young female who presented with bilateral ovarian masses that mimicked the classic clinical picture of ovarian cancer. The patient had a cytoreductive surgery done in the form of total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, pelvic peritonectomy, low para-aortic and bilateral iliac lymphadenectomy. Postoperative course was smooth with no adverse events. The final pathology report revealed desmoplastic small-round-cell tumor. Afterwards, the patient was referred to medical oncologist to receive her adjuvant therapy.

CONCLUSIONS

DSRCT is still an unknown disease to us given the limited number of cases and poor survival. Given the lack of clear guidelines, treatment is offered based on the best available evidence and the collaborative effort of a multi-disciplinary team.

Sinonasal desmoplastic small round cell tumor: a case report and review of the literature

BACKGROUND

Desmoplastic small round cell tumor (DSRCT) is a rare malignancy with poor prognosis that generally involves the peritoneum. Its diagnosis can be achieved only by immunohistochemistry and cytogenetic studies.

CASE PRESENTATION

In the current report, a 55-year-old female was admitted in our hospital for evaluation of right eye epiphora and right nasal intermittent bleeding. Imaging examination revealed a large soft tissue mass in the right nasal cavity and ethmoid sinus. After an explorative surgery, the pathological findings confirmed the presentation of sinonasal DSRCT. Immunohistochemistry and cytogenetic studies confirmed the diagnosis of DSRCT in this patient. Surgical resection, chemotherapy, and radiotherapy was performed, and she died 2 months after operation.

CONCLUSION

This reported case draws attention to the importance of novel treatments and including DSRCT in the differential diagnosis of sinonasal tumors.

Non-islet Cell Tumor-induced Hypoinsulinemic Hypoglycemia in the Setting of Metastatic Desmoplastic Round Cell Tumor

A 24-year-old male with metastatic desmoplastic round cell tumor was admitted for fatigue and weakness after chemotherapy. The patient was found to be hypotensive, pancytopenic, and bacteremic. Early treatment with intravenous antibiotics and fluids was efficacious. The hospital course was complicated by recurrent hypoglycemia that was refractory to the standard hypoglycemia protocol. Initial workup revealed low serum insulin and normal C-peptide. Further evaluation revealed elevated IGF-II levels consistent with non-islet cell tumor-induced hypoglycemia. Euglycemia was subsequently achieved with aggressive and continuous infusion of intravenous 10% dextrose.

Desmoplastic Small Round Cell Tumor: Imaging Pattern of Disease at Presentation

OBJECTIVE

The purpose of this study is to evaluate the clinical, pathologic, and multimodality cross-sectional imaging features of a cohort of 94 patients with desmoplastic small round cell tumor (DSRCT).

MATERIALS AND METHODS

This retrospective study of 94 patients with pathologically verified DSRCT was conducted at a tertiary cancer center between 2001 and 2013. Epidemiologic, clinical, pathologic, and imaging findings were recorded. Tumor size, location, and shape and the distribution pattern of metastases at presentation were analyzed.

RESULTS

DSRCT most often occurred in young patients (median age, 21.5 years; range, 5-53 years), showing a marked predominance in male patients (86 male patients vs eight female patients). Eighty nine-patients (95%) were white (defined in this study as white or Hispanic), four were African American, and one was of Asian descent. Most patients had symptoms, with abdominal pain noted as the most common symptom. At initial presentation, 85 patients (90%) had multifocal disease, nodular disease, diffuse omental and peritoneal disease, or a combination of these conditions. Thirty-eight patients (40%) had diaphragmatic involvement. Thirty-two patients (34%) had liver metastases, and 49 patients (52%) had retroperitoneal involvement in the form of implants, tumoral extension, or nodal involvement. With regard to thoracic findings, 33 patients (35%) had nodal disease, 17 (18%) had pleural effusions, and only two (2%) had lung metastases at presentation. Twelve patients (13%) had calcified lesions.

CONCLUSION

DSRCT is a rare, multifocal peritoneal malignancy with frequently disseminated abdominal disease at presentation. In the abdomen, disease most commonly involves the omentum and peritoneum, followed by the retroperitoneum. The liver is the most common solid visceral metastatic site. A substantial number of patients have diaphragmatic involvement. In the thorax, nodal and pleural involvement is more common than lung involvement.

Primary desmoplastic small round cell tumor in the left orbit: a case report and literature review

PURPOSE

Desmoplastic small round cell tumor is a rare malignant neoplasm that most often occurs in the abdomen or pelvis of young men. We herein describe a rare case of desmoplastic small round cell tumor arising from the left orbit in a 16-year-old male.

METHODS AND RESULTS

A biopsy was performed and the histology showed the nests of tumor cells with small round cell morphology. The tumor cells showed immunopositivity for desmin, CD99, CD56, SMA, NSE, CgA, SYN, Ki67 and vimentin. Fluorescence in situ hybridization study using EWSR1 break-apart probe was positive for EWSR1 gene rearrangement. After complete surgical resection of the tumor, we did not find tumor recurrence or metastasis with one-year follow-up. Furthermore, a review of the relevant English literature has been discussed.

CONCLUSIONS

In the present study, for the first time, we report a case of desmoplastic small round cell tumor which is located in the orbital region.

Pictorial review of 18F-FDG PET/CT findings in musculoskeletal lesions

We herein reviewed ¹⁸F-fluoro-2-deoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) findings in a number of musculoskeletal lesions including malignant tumors, benign tumors, and tumor-like lesions with correlations to other radiographic imaging modalities, and described the diversity of the ¹⁸F-FDG PET/CT findings of this entity. Malignant primary musculoskeletal tumors are typically ¹⁸F-FDG avid, whereas low-grade malignant tumors show mild uptake. Benign musculoskeletal tumors generally show a faint uptake of ¹⁸F-FDG, and tumor-like conditions also display various uptake patterns of ¹⁸F-FDG. Although musculoskeletal tumors show various uptakes of ¹⁸F-FDG on PET/CT, its addition to morphological imaging modalities such as CT and MRI is useful for the characterization and differentiation of musculoskeletal lesions.

Management of desmoplastic small round cell tumor

Desmoplastic small round cell tumor (DSRCT) is a soft tissue sarcoma of mesenchymal cell origin that typically presents with multiple intra-abdominal tumors and exhibits a multi-phenotypic pattern of immunohistochemical staining. The specific organ or tissue type of origin has yet to be identified. DSRCT rarely arises as a singular tumor in the abdomen; in most cases, there are dozens to hundreds of abdominal peritoneal tumors that are detected on diagnosis. One very large dominant mass is usually present in the omentum, with an additional one or two large conglomerates of tumors in the pelvis and right peritoneum, respectively. Despite an often overwhelmingly large number of abdominal tumors, symptoms of bowel obstruction are rare. Ascites may be present. In late stages, pleural effusions, pleural implants, mediastinal adenopathy, supraclavicular adenopathy, or bone metastasis may be present. With this challenging disease, multidisciplinary therapy, including aggressive surgery, is warranted. This review will address DSRCT biology and treatment options and discuss outcomes.

Desmoplastic small round cell tumor: postoperative retroperitoneal mass

We describe the case of a 14-year-old boy who presented with a large, 17.6-cm retroperitoneal mass, along with multiple metastases, and was diagnosed with desmoplastic small round cell tumor. After initial chemotherapy, he underwent gross total resection with a positive margin. On postoperative radiation planning computed tomography, a 6.8-cm heterogeneous mass was noted in the surgical bed. Given the tumor's aggressive nature and positive surgical margins, there was real concern for recurrent disease. Further evaluation with magnetic resonance imaging elucidated that the mass consisted of simple fluid and fat, without contrast enhancement, suggesting a postoperative fluid collection. He was able to continue with adjuvant treatment as planned. This case example illustrates that even large postoperative heterogeneous masses may still be related to postoperative fluid collection in patients with aggressive tumor. However, it is important to rule out recurrent disease before starting adjuvant therapy given improved outcomes with gross total resection in desmoplastic small round cell tumor.

Intra-abdominal desmoplastic small round cell tumour: staging and surveillance with 18F-FDG PET/CT following peritonectomy and HIPEC

Intra-abdominal desmoplastic small round cell tumours are rare aggressive tumours of mesothelial origin with less than 60 cases reported in the literature. They are difficult to treat and the role of ¹⁸F-fludeoxyglucose positron emission tomography (PET)/CT scan in their management has not been established. A 41-year-old male presented with a 21-cm desmoplastic small round cell tumour and was managed with radiotherapy, surgery and chemotherapy, with each treatment monitored and guided by ¹⁸F-fludeoxyglucose PET/CT scan. We present the imaging findings of the serial PET/CT scans of this patient and their impact on management.

Intra-abdominal desmoplastic small round cell tumors: CT and FDG-PET/CT findings with histopathological association

Desmoplastic small round cell tumors (DSRCTs) are rare and aggressive malignant tumors. The aim of the present study was to analyze computed tomography (CT) and fluorodeoxyglucose positron emission tomography (FDG-PET)/CT imaging features of intra-abdominal desmoplastic DSRCT, and investigate the association of these features with histopathological results. The present study was a retrospective investigation of 4 patients with DSRCT. All patients underwent CT and dynamic CT, and 1 additionally underwent FDG-PET/CT scanning. Following a tumor resection, routine hematoxylin and eosin staining, and immunostaining, were performed and evaluated. Multiple large abdominopelvic masses were identified in all 4 patients; however, no indications of their site of origin were demonstrated. CT revealed soft-tissue masses with patchy foci of hypodense lesions. Contrast-enhanced CT revealed slightly or moderately heterogeneous enhancement of the lesions. Other observations from these patients included calcification (n=2), peritoneal seeding (n=3), hepatic metastasis (n=3), retroperitoneal lymphadenopathy (n=3) and ascites (n=2). FDG-PET/CT revealed multiple nodular increased FDG uptake in the abdominopelvic masses, and in the liver and peritoneum in 1 case. Intra-abdominal DSRCT demonstrated significant diagnostic characteristics on plain and contrast-enhanced CT. Multiple, bulky soft-tissue masses inside the peritoneal cavity, particularly in male adolescents and young adults, should be considered as potential cases of DSRCT. FDG-PET/CT techniques may be utilized to aid the staging of tumors.

Assessing the role of ¹⁸F-FDG PET and ¹⁸F-FDG PET/CT in the diagnosis of soft tissue musculoskeletal malignancies: a systematic review and meta-analysis

PURPOSE

Twelve years ago a meta-analysis evaluated the diagnostic performance of (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in assessing musculoskeletal soft tissue lesions (MsSTL). Currently, PET/CT has substituted PET imaging; however, there has not been any published meta-analysis on the use of PET/CT or a comparison of PET/CT with PET in the diagnosis of MsSTL. Therefore, we conducted a meta-analysis to identify the current diagnostic performance of (18)F-FDG PET/CT and determine if there is added value when compared to PET.

METHODS

A systematic review of English articles was conducted, and MEDLINE PubMed, the Cochrane Library, and Embase were searched from 1996 to March 2015. Studies exploring the diagnostic accuracy of (18)F-FDG PET/CT (or dedicated PET) compared to histopathology in patients with MsSTL undergoing investigation for malignancy were included.

RESULTS

Our meta-analysis included 14 articles composed of 755 patients with 757 soft tissue lesions. There were 451 (60 %) malignant tumors and 306 benign lesions. The (18)F-FDG PET/CT (and dedicated PET) mean sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for diagnosing MsSTL were 0.96 (0.90, 1.00), 0.77 (0.67, 0.86), 0.88 (0.85, 0.91), 0.86 (0.78, 0.94), and 0.91 (0.83, 0.99), respectively. The posterior mean (95 % highest posterior density interval) for the AUC was 0.92 (0.88, 0.96). PET/CT had higher specificity, accuracy, and positive predictive value when compared to a dedicated PET (0.85, 0.89, and 0.91 vs 0.71, 0.85, and 0.82, respectively).

CONCLUSION

(18)F-FDG PET/CT and dedicated PET are both highly accurate in the diagnosis of MsSTL. PET/CT is more accurate and specific and has a higher positive predictive value than PET.

Desmoplastic small round cell tumor of the lung: A case report and literature review

Desmoplastic small round cell tumor (DSRCT) is a rare, aggressive and malignant tumor that is characterized by nests of small tumor cells surrounded by a cellular and vascular collagenous stroma and predominantly affects young adolescent males. This tumor most commonly originates in the abdomen; however, in rare cases, DSRCT can originate in other body regions. The main manifestations of DSRCT are chest pain and respiratory symptoms, and patients' average survival after diagnosis is less than two years. In this report, we describe a case involving DSRCT of the lung that proved to be difficult to diagnose, and we conduct a literature review.

FDG PET/CT imaging of desmoplastic small round cell tumor: findings at staging, during treatment and at follow-up

BACKGROUND

Desmoplastic small round cell tumor (DSRCT) is a very uncommon soft-tissue tumor of children and young adults. It has an aggressive course with generally poor survival. In general the assessment of tumor burden and response has relied upon CT or MRI. However these tumors are often metabolically active and can be evaluated using FDG PET/CT imaging.

OBJECTIVE

The purpose of this study was to determine the metabolic activity of desmoplastic small round cell tumors using FDG PET/CT imaging and the potential utility of FDG PET/CT in this disease.

MATERIALS AND METHODS

Eight patients (seven male, one female; ages 2-20 years, median 11 years) with confirmed DSRCT underwent 82 positron emission tomography/computed tomography (PET/CT) scans. PET/CT was used for initial staging (seven patients, eight scans), monitoring response to therapy (eight patients, 37 scans) and for surveillance of DSRCT recurrence (six patients, 37 scans).

RESULTS

Each scan performed at diagnosis showed abnormally elevated uptake in the primary tumor. Five patients had abdominal pelvic involvement, and two of those also had thoracic disease. Six patients whose scans showed no abnormal sites of uptake at the end of therapy have had progression-free survivals of 2-10 years. One patient whose scan continued to show uptake during treatment died of disease 1.3 years from diagnosis. Another patient with persistent uptake remained in treatment 3 years after initial diagnosis. One surveillance scan identified recurrent disease.

CONCLUSION

FDG PET/CT identified elevated metabolic activity in each patient studied. Despite our small sample size, FDG PET/CT scans appear useful for the management of patients with DSCRT. Patients whose studies become negative during or following treatment may have a prolonged remission.

Primary malignant tumors of peritoneal and retroperitoneal origin: clinical and imaging features

Peritoneal carcinomatosis and metastatic involvement of the retroperitoneum are manifestations of many organ-based malignancies and lymphoproliferative disorders. Primary malignancies of peritoneal and retroperitoneal origin occur much less frequently, and are difficult to distinguish from metastatic disease on imaging alone. However, the imaging features of these primary tumors, taken in concert with the clinical data, can be helpful in narrowing the scope of the differential diagnosis. This review presents the clinical and imaging features of primary peritoneal and retroperitoneal tumors arising from the various tissue components that comprise the ligaments, mesenteries, and connective tissues of the peritoneal and retroperitoneal spaces.

Testicular desmoplastic small round cell tumor: a case report and review of literature

Background

Desmoplastic small round cell tumor (DSRCT) is an uncommon and highly aggressive malignancy with undetermined histogenesis and poor prognosis. To date, no case of testicular DSRCT has been reported in the literature.

Case

A 42-year-old Chinese man presented with painless swelling of his left testis and a painless palpable nodule in his left inguinal region. Computed tomography showed a solid mass in the left testis and multiple metastases in the body. Laboratory tests gave no abnormal results. Left radical orchiectomy was performed, and histopathological and molecular pathological examination showed typical features of DSRCT. Six cycles of chemotherapy were administrated after the operation, leading to partial remission. Postoperative 9-month follow-up indicated no progression.

Desmoplastic small round cell tumor: a rare cause of a progressive brachial plexopathy

INTRODUCTION

Desmoplastic small round cell tumor (DSRCT) is an uncommon, embryonic-type neoplasm, typically presenting as an abdominal mass in young men. A single case of DSRCT arising in the peripheral nervous system has been reported previously.

METHODS

The clinical course, imaging, electrophysiological, intraoperative, histopathological, molecular findings, and postoperative follow-up are reported.

RESULTS

A 43-year-old man presented with slowly progressive right brachial plexopathy. Magnetic resonance imaging revealed an enlarged medial cord with heterogeneous contrast enhancement. Histology showed a "small round cell" neoplasm with a polyphenotypic immunoprofile, including epithelial and mesenchymal markers. A pathognomonic fusion of Ewing sarcoma breakpoint region 1 and Wilms tumor 1 genes (EWSR1/WT1) was present. Treatment involved gross total excision and local radiotherapy.

CONCLUSIONS

Our findings confirm the occurrence of DSRCT as a primary peripheral nerve tumor. Despite its usually very aggressive clinical course, prolonged recurrence-free survival may be reached. Histomorphology and immunoprofile of DSRCT may lead to misdiagnosis as small cell carcinoma.

Clinical and computed tomography features of adult abdominopelvic desmoplastic small round cell tumor

To investigate the clinical and computed tomography (CT) features of desmoplastic small round cell tumor (DSRCT), we retrospectively analyzed the clinical presentations, treatment and outcome, as well as CT manifestations of four cases of DSRCT confirmed by surgery and pathology. The CT manifestations of DSRCT were as follows: (1) multiple soft-tissue masses or diffuse peritoneal thickening in the abdomen and pelvis, with the dominant mass usually located in the pelvic cavity; (2) masses without an apparent organ-based primary site; (3) mild to moderate homogeneous or heterogeneous enhancement in solid area on enhanced CT; and (4) secondary manifestations, such as ascites, hepatic metastases, lymphadenopathy, hydronephrosis and hydroureter. The prognosis and overall survival rates were generally poor. Commonly used treatment strategies including aggressive tumor resection, polychemotherapy, and radiotherapy, showed various therapeutic effects. CT of DSRCT shows characteristic features that are helpful in diagnosis. Early discovery and complete resection, coupled with postoperative adjuvant chemotherapy, are important for prognosis of DSRCT. Whole abdominopelvic rather than locoregional radiotherapy is more effective for unresectable DSRCT.

Removal of an intra-abdominal desmoplastic small round cell tumor by repetitive debulking surgery: A case report and literature review

In the current study, a case of recurrent desmoplastic small round cell tumor (DSRCT) is presented, which was successfully treated by repetitive debulking surgery. In May 2010, a 39-year-old male, with a history of surgical resection of intra-abdominal DSRCT, visited the Ibaraki Medical Center, Tokyo Medical University Hospital (Ami, Japan) with severe lower abdominal discomfort. Abdominal computed tomography revealed a large tumor in the pouch of Douglas with a small number of nodules in the abdominal cavity. The recurrent DSRCT was diagnosed and removed via lower anterior resection; however, complete resection was impossible due to multiple peritoneal metastases. One year later, the patient developed pain in the right groin due to the growth of metastasized tumor cells in the groin lymph nodes. The affected lymph nodes were removed utilizing an extra-peritoneal approach. At the time of writing, the patient continues to survive without any symptoms 60 months since the initial surgery. In conclusion, surgical debulking is a significant procedure for relieving patient symptoms as well as improving the survival time of patients with metastatic and recurrent DSRCT.

Desmoplastic small round cell tumor of stomach

Desmoplastic small round cell tumor (DSRCT) is an extremely uncommon, highly aggressive, and malignant mesenchymal neoplasm of undetermined histogenesis. Less than 200 case reports have been documented in literature so far. Herein, we report a 26-year-old otherwise healthy female patient who presented with a 1-month history of epigastric pain. On physical examination, a palpable, slightly mobile, and tender epigastric mass was detected. All laboratory tests were normal. A chest, abdominal, and pelvic contrast-enhanced computed tomography (CT) scans showed a 3.8 × 7.2 × 8.7 cm ill-defined mass, involving gastric fundus and extending into gastric cardia and lower gastroesophageal junction. It was associated with multiple enlarged gastrohepatic lymph nodes; the largest measured 1.2 cm. There was no evidence of ascites or retroperitoneal or mesenteric lymphatic metastases. Patient underwent total gastrectomy with D2 lymphadenectomy, splenectomy, and antecolic Roux-en-Y esophagojejunal anastomosis. Histopathological examination revealed coexpression of mesenchymal, epithelial, and neural markers. The characteristic chromosomal translocation (t(11; 22)(p13; q12)) was demonstrated on fluorescence in situ hybridization (FISH) technique. Diagnosis of DSRCT of stomach was confirmed. Patient received no postoperative radiotherapy or chemotherapy. A postoperative 3-month followup failed to show any recurrence. In addition, a literature review on DSRCT is included.

Positron emission tomography for response assessment in desmoplastic small round cell tumor

BACKGROUND

Desmoplastic small round cell tumors (DSRCT) typically have a large stromal component and often are extensively disseminated in the peritoneal cavity at diagnosis. These factors contribute to difficulty in quantifying response to chemotherapy using RECIST or WHO criteria. This study compares the overall disease response to chemotherapy by fluorodeoxyglucose-positron emission tomography (FDG-PET) and computed tomography (CT) in patients with DSRCT.

METHODS

We conducted a retrospective chart review of 7 patients with DSRCT who were imaged by FDG-PET and CT at diagnosis and after 3 cycles of chemotherapy. Response to chemotherapy was graded according to EORTC metabolic response guidelines and RECIST.

RESULTS

All tumors demonstrated some decrease in SUVmax (51%±21%) and longest diameter (23%±8%) with chemotherapy. The best response achieved by FDG-PET was a partial response in 6 patients and by CT was a partial response in 1 patient. Measured response was concordant between the 2 modalities in 2 patients.

CONCLUSIONS

In this small series response measurement by FDG-PET did not always correlate with response measurement by CT. A greater decrease in metabolic activity as compared with size was seen in all patients. Further studies are needed to define the role of FDG-PET in assessing early response of DSRCT to chemotherapy.

Imaging of pediatric desmoplastic small-round-cell tumor with pathologic correlation

Desmoplastic small-round-cell tumors are rare aggressive malignancies that belong to the "small round blue cell" tumor family. They predominantly affect the abdomen in adolescent and young adult males. Computed tomography is currently the modality of choice both for diagnosis and follow-up assessment. In this review, the authors provide a concise yet comprehensive discussion of this condition with emphasis on the imaging findings. Pathologic correlation, differential diagnostic considerations, and treatment will also be presented.

Desmoplastic small round cell tumour: the radiological, pathological and clinical features

OBJECTIVES

Desmoplastic small round cell tumours (DSRCTs) are rare aggressive tumours of young adults that present late and have poor prognosis. This review discusses distinctive radiological features, histopathology and clinical course of this soft-tissue sarcoma.

METHODS

From 1991 to 2012, the radiology of 20 patients with pathologically proven DSRCT was independently reviewed by two experienced radiologists. The clinical presentation, treatment and outcome were recorded.

RESULTS

PATIENTS

16 men, four women; mean age 28.3 years. Computed tomography (CT) demonstrated peritoneal/omental masses without an organ of origin (94 %), with the majority of cases demonstrating large (>5 cm) dominant soft-tissue deposit (80 %) with multiple smaller foci. CT and magnetic resonance imaging (MRI) typically demonstrated heterogeneous soft-tissue enhancement with cystic degeneration. A minority (20 %) demonstrated calcification. Lymph node enlargement occurred in 50 % of cases. Distant metastatic disease occurred in 25 %. Painful abdominal masses were clinically predominant. Treatment strategies include combination chemotherapy with debulking surgery and/or radiotherapy. Median survival from diagnosis was 22.8 months.

CONCLUSION

Features of multifocal peritoneal/omental masses, usually in combination with a dominant soft tissue deposit, are distinctive in this rare sarcoma. CT/MRI defines the extent of disease and characterises supporting imaging findings. Prolific desmoplastic reaction histologically separates DSRCT from similar subtypes. Combination treatment strategies can infer a survival benefit but prognosis remains poor. TEACHING POINTS : • DSRCTs are rare tumours of young adults (mean age 28.3 years) with a male predominance (4:1). • Painful abdominal masses clinically predominate. Non-specific features of malignancy can be present. • Multifocal peritoneal masses with a dominant soft tissue lesion is a distinctive imaging finding. • A large desmoplastic reaction differentiates DSRCTs from histologically similar round cell subtypes. • Despite debulking surgery with adjuvant chemotherapy, median survival from diagnosis is 22.3 months.

Peritoneal sarcomatosis in pediatric malignancies

Peritoneal sarcomatosis (PSC) is defined as peritoneal involvement of multiple sarcomatous tumors. Desmoplastic small round cell tumors (DSRCT) and rhabdomyosarcomas are the most common pediatric PSC cases. PSC has been treated with chemotherapy and mainly palliative surgery, but long-term outcome has been poor. New imaging technologies have improved the evaluation of disease extent and patterns of peritoneal dissemination, and cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy (HIPEC) is being evaluated as a treatment option to prolong remission in pediatric patients. We will review the clinical characteristics, potential biologic mechanisms, radiographic characteristics, and potential therapies for pediatric PSC patients.

Characteristic imaging features of desmoplastic small round cell tumour

BACKGROUND

Desmoplastic small round cell tumour (DSRCT) is a rare malignant neoplasm. Its radiological features have rarely been described.

OBJECTIVE

To assess the CT parameters characteristic of DSRCT. We also report our experience with combined FDG PET/CT in staging and follow-up for DSRCT.

MATERIALS AND METHODS

The pretreatment diagnostic CT's of 65 patients with DSRCT were evaluated. Pertinent imaging findings were catalogued, with histopathology or serial follow-up studies as reference standard. Combined FDG PET/CT examinations of 11 of these patients who underwent pretreatment imaging were also reviewed.

RESULTS

Sixty-two patients presented with primary intra-abdominal disease; three had primary extra-abdominal tumours at presentation. The most common imaging finding of patients with intra-abdominal DSRCT was multiple peritoneal soft tissue masses, with a dominant mass in the retrovesical or rectouterine location in more than half of the cases. Forty percent had metastatic disease to the liver, lungs, spleen or bones at diagnosis. FDG PET/CT accurately detected 97.4% of all DSRCT lesions.

CONCLUSION

DSRCT typically presents as a large abdominopelvic mass with widespread peritoneal involvement predominantly in young males. Familiarity with its radiological features can help guide diagnosis and treatment. Functional imaging with PET/CT offers advantage over anatomical imaging for accurate disease staging.

Recent advances in non-rhabdomyosarcoma soft-tissue sarcomas

Nonrhabdomyosarcoma soft-tissue sarcomas (NRSTS) represent a subgroup of sarcomas that encompass more than 50 distinct histologies. All are rare, but some are more common in patients younger than 20 years of age. The management of patients with many histologies overlap. However, this review will focus on issues unique to a select few NRSTS that are most common in pediatric and adolescent patients. Here, we will discuss the recent advances in the diagnosis, surgical management, and treatment of NRSTS. Adequate surgical local control of the primary tumor is a critical component of the treatment strategy will be emphasized in this review because it determines local and distant recurrence.

A rapidly developing lung mass diagnosed as desmoplastic small round cell tumor

We present a case of a young male who presented with complaints of fever along with cough and sputum. He was diagnosed with having right pleural effusion. He was already taking anti-tubercular therapy for one month before presentation. He was started on intravenous antibiotics and continued on anti-tubercular therapy in our hospital, based on his high leukocyte count, pleural fluid analysis, and ultrasonographic report of multiple hypoechoic areas in the liver. His symptoms continued to worsen and he subsequently developed mediastinal widening and a left lung mass. Commuted tomography (CT)-guided biopsy of the lung mass revealed a desmoplastic small-round-cell tumor. Desmoplastic small-round-cell tumor is a rare and aggressive tumor, which presents rarely as a mediastinal and lung mass. This tumor has very poor prognosis.