Intraabdominal desmoplastic small round cell tumor presenting as a gastric mural mass with hepatic metastases

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 Ewing's Sarcoma of the Duodenum: A Case Report

We report a case of Ewing's sarcoma arising from the duodenum in a 20-year-old woman who presented with a rapidly progressive ulcerative lesion. The surgical specimen obtained via Whipple's operation revealed a small round-cell tumor (SRCT) in the first and second portion of the duodenum. The tumor cells revealed strong immunoreactivity for CD 99 and vimentin and focal paranuclear dot-like immunoreactivity for cytokeratin. Electron microscopy showed primitive tumor cells with few cytoplasmic organelles, but neither neurosecretory granules nor specific cell junctions were present. On Western blot study, 68-kDa EWS/FLIl fusion protein was detected. The occurrence of Ewing's sarcoma in the gastrointestinal hollow viscus has recently been recognized, and this case expands the known anatomic sites that can harbor Ewing's sarcoma by demonstrating primary duodenal involvement.

Desmoplastic small round cell tumor of the stomach mimicking a gastric cancer in a child

Intra-abdominal desmoplastic small round cell tumor (DSRCT) is a highly malignant tumor of uncertain histogenesis. Here we report a case of DSRCT involving the stomach, initially misdiagnosed as gastric cancer. A 12-year-old boy presented with upper abdominal pain developed 1 month prior. On gastroscopy, a 7-cm mass was noted involving the esophago-gastric junction to the fundus, and positron emission tomography showed multiple hot uptakes suggesting distant metastasis. Gastroscopic biopsy showed poorly differentiated malignant cells. We diagnosed as stage IV gastric cancer and treated with 6 cycles of chemotherapy. Laparotomy revealed a huge gastric mass along with peritoneal disseminations. Palliative proximal gastrectomy was performed. Pathological examination revealed transmural involvement of DSRCT, and t(11;22)(p12;q12) was demonstrated on fluorescence in situ hybridization test. The chemotherapeutic regimen was changed and the patient underwent 8 additional cycles of post-operative chemotherapy. The patient is now alive and the residual tumor shows no significant changes after chemotherapy.

Desmoplastic small cell tumor of soft tissue: molecular variant of EWS-WT1 chimeric fusion

A 7-year-old girl was hospitalized because of a tumorous mass in her left periorbital region. The tumor was removed by local excision. The soft-part tumor recurred in the parotid gland region 4 months later, and a second recurrence was noted on the left side of the neck 3 years and 3 months thereafter. The patient had not received chemotherapy or local irradiation. Histological and immunohistochemical examinations of the recurrent masses revealed morphological characteristics of small cell proliferation with desmoplastic stroma that were similar to those of the initial tumor. The cellular components showed immunoreactivity for desmin, cytokeratin, vimentin, and epithelial membrane antigen in part, but the cells were negative for myogenin, CD99, and neuron-specific enolase. These findings suggested a diagnosis of desmoplastic small cell tumor, despite its extra-abdominal location. The histological diagnosis was confirmed by reverse transcriptase polymerase chain reaction, which demonstrated an EWS-WT1 chimeric fusion gene. An in-frame fusion of EWS exon 9 and WT1 exon 8 was subsequently identified by cloning and sequencing. The chimeric fusion gene might be related to the tissue-specific phenotype of desmoplastic small cell tumors, although further investigation of this speculation is necessary.

Intra-abdominal desmoplastic small round cell tumors: CT findings and clinicopathological correlations in 13 cases

PURPOSE

We report computed tomography (CT) findings in 13 patients with a primary abdominal desmoplastic small round cell tumor.

MATERIALS AND METHODS

13 cases (12 men, 1 woman, mean age=24.8 years) were found in our hospital database between 1991 and 2003. Clinical, CT and histopathological features were studied retrospectively.

RESULTS

Peritoneal involvement was the most common feature. In 10 cases, several lobulated peritoneal soft tissue masses (with a mean of four masses per patient) were seen. Two patients had diffused irregular peritoneal carcinomatosis without any distinct peritoneal masses. One patient had a solitary mass in the pelvic space. The main sites of peritoneal involvement were the pelvic space (n=7), omentum (n=5), retroperitoneal space (n=4), small bowel mesentery (n=3), paracolic gutter (n=2 on the right and n=1 on the left), transverse colon mesentery (n=1), peri-splenic space (n=1), peri-hepatic space (n=1). The soft tissue masses were often bulky (mean 6cm, range 1-28cm), lobulated and heterogeneous with hypodense areas (in 73% of cases). In six cases, moderate ascites was seen. In one case of pelvic involvement, unilateral hydronephrosis was seen. Adenopathies were present in seven cases at the time of the diagnosis (at intraperitoneal, retroperitoneal and pelvic sites in six patients and in the groin in one patient). Five patients had liver metastases (four lesions per case excepted one patient with 30 metastases). Associated thoracic metastases were seen in three patients. The diagnosis was confirmed with four CT-guided percutaneous biopsies.

CONCLUSION

Although CT features are nonspecific, the diagnosis of desmoplastic small round cell tumor may be suspected in young men with multiple bulky heterogeneous peritoneal soft tissue masses. Imaging is useful for staging and also to guide biopsies.

Retrovesical desmoplastic small round cell tumor in a patient with urinary frequency

A 21-year-old man with urological symptoms was found to have a large abdominal tumor in the retrovesical space between the bladder and the rectosigmoid colon. Radiologic findings revealed little evidence confirming the diagnosis. A transrectal biopsy failed to disclose the histopathologic origin of the tumor. An exploratory laparotomy with a complete surgical resection was impossible, so a wedge biopsy was performed. Combined histologic and immunohistochemical findings revealed the features of desmoplastic small round cell tumor (DSRCT). Despite subsequent multi-agent chemotherapy, the patient died as a result of the growing tumor and liver metastasis. There have been only two prior reports of this neoplasm in the urological literature.

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

Desmoplastic small round cell tumor (DSRCT) is a rare neoplasm mainly affecting young males and typically located in the abdomen. Prognosis is generally very poor. We report a rare case of paratesticular DSRCT in a 17-year-old boy, presenting with an isolated left scrotal mass. The patient had an excellent outcome after complete surgical resection of the tumor and adjuvant multi-agent chemotherapy. DSRCT should be included in the differential diagnosis of small round cell tumors of the paratesticular region in adolescents and young adults. Tumor resection and chemotherapy may be beneficial for these patients. Our experience and a review of the literature suggest that DSRCT located in the paratesticular region may have a better prognosis than its more frequent abdominal counterpart.

Desmoplastic small round cell tumor: II: an ultrastructural and immunohistochemical study with emphasis on new immunohistochemical markers

In order to investigate the histogenesis and facilitate the diagnosis of desmoplastic small round cell tumor (DSRCT), 39 cases were studied by immunohistochemical methods using a large battery of antibodies directed against a wide variety of epithelial, mesenchymal, and neural-associated proteins. Sixteen of these tumors were also studied by electron microscopy. Thirty-seven of 39 cases reacted for cytokeratin using a "cocktail" of 3 monoclonal antibodies (CAM 5.2/AE1/AE3), 39/39 for desmin, 24/25 for epithelial membrane antigen, 22/27 for vimentin, 18/25 for neuron-specific enolase, 10/15 for CD57 (Leu-7), 3/19 for synaptophysin, 1/22 for chromogranin, 3/19 for muscle-specific actin, 3/16 for alpha-smooth-muscle actin, 11/16 for CD15 (Leu-M1), 5/12 for CA-125, 6/17 for CD99, 9/10 for MOC-31, 2/6 for NB84, 5/7 for Ber-EP4, and 8/9 for the Wilms tumor (WT1) protein. No staining was obtained in any of the cases tested for cytokeratin 5/6 or 20, neurofilament proteins, glial fibrillary acidic protein, peripherin, CA19-9, thrombomodulin, alphafetoprotein, carcinoembryonic antigen, TAG-72 (B72.3), placental alkaline phosphatase, S-100 protein, HMB-45, myoglobin, or for the two myogenic regulatory proteins myogenin and MyoD1. A frequent ultrastructural finding was the presence of juxtanuclear aggregates of intermediate filaments, but microfilaments with densities or Z-band-like material suggestive of either smooth or skeletal muscle differentiation were not seen in any case. Dendritic-like processes containing microtubules and dense core granules were seen in four tumors and all of these tumors reacted for at least one of the neural markers investigated. Although ultrastructural and immunohistochemical studies confirmed previous observations that DSRCTs present epithelial, mesenchymal, and neural phenotypes, a great variation was found in the frequency of expression of the different markers used to demonstrate each line of cell differentiation. The absence of expression of cytokeratin 5/6 and thrombomodulin together with positive staining for CD15, MOC-31, and Ber-EP4 argues against the possible mesothelial origin that has been suggested for this tumor. Additionally since none of the tumors reacted for myogenin or MyoD1, desmin expression in DSRCT cannot be regarded as evidence of skeletal muscle differentiation. Although the histogenesis of DSRCT remains unknown, it is believed that this tumor originates from a progenitor cell with potential for multiphenotypic differentiation.

Desmoplastic small round cell tumour

The present report describes a rare case of primary desmoplastic small cell tumour of the recto-sigmoid colon with hepatic metastases and lymphadenopathy. There are no pathognomonic radiological features and often their features overlap with other diseases including lymphoma. Histology is necessary to confirm this diagnosis. Unfortunately despite aggressive therapy, the prognosis for this disease is poor.

Desmoplastic small round cell tumors: prognostic indicators and results of surgical management

BACKGROUND

Desmoplastic small round cell tumors (DSRCT or DSCT) are rare aggressive cancers of adolescence and early adulthood. There are few reported series to guide clinical therapy. This study correlates survival with treatment variables, including aggressive surgical debulking.

METHODS

Thirty-two patients with documented DSRCT received treatment at our institution. Demographic, clinical, and treatment variables were correlated with progression-free survival using log-rank statistics.

RESULTS

Thirty patients were male (96%), and two were female (4%), with a median age at diagnosis of 22 years. The primary site of disease in 97% of cases was the abdomen or pelvis. Twenty-nine patients (91%) had extensive disease involving peritoneal surfaces, lymph nodes, or discontinuous organs. All 32 patients received systemic chemotherapy. Fifteen (47%) underwent tumor debulking greater than 90% at diagnosis or during therapy. A complete or very good response to therapy occurred in 13 patients, and depended on surgical removal of bulk disease in all. Thirteen patients remained progression-free, but three of these patients died from treatment toxicity. Improved survival was correlated with a complete or very good partial response to multimodality therapy, surgical debulking of more than 90% either before or after chemotherapy, and use of the P6 protocol.

CONCLUSIONS

DSRCT is an aggressive cancer that occurs predominantly in young males. Improved survival is correlated with intense chemotherapy and aggressive resection.