Desmoplastic small round cell tumor in transverse colon: report of a rare case.

Desmoplastic small round cell tumor (DSRCT) is an extremely rare, highly aggressive, malignant tumor of undetermined histogenesis. Adolescent males are primarily affected with a typically abdominal or pelvic mass. Diagnosis is based on histologic analysis of biopsy and cytogenetic studies. Owing to the rarity of the tumor and the unusually aggressive presentation, treatment is challenging and has not been standardized. DSRCT has a very poor prognosis, with a median survival range of 17 to 25 months. In this work, we report a case of DSRCT in the transverse colon, which has never before been reported in the literature. Our case study is of a 30-year-old Chinese female who presented with a history of 6 months abdominal discomfort and fatigue. A palpable, hardly mobile mass was detected in the right lower quadrant abdomen by physical examination. Abdominal and pelvic magnetic resonance imaging revealed an 8.0 × 10.5 × 11.1-cm mass with no pulmonary and hepatic metastasis. The patient underwent exploratory laparotomy and transverse colectomy, which revealed a mass in the transverse colon and no metastasis in the peritoneum, greater omentum, or mesentery. Immunohistochemistry findings revealed positive staining for epithelial, mesenchymal, and neural markers, which confirmed the presentation of DSRCT. A 6-month postoperative follow-up failed to find any recurrence. DSRCT is a highly aggressive, malignant, mesenchymal tumor with a very poor prognosis. No consensus has been reached for the treatment protocol of DSRCT. However, debulking surgery with postoperative chemotherapy or radiotherapy might promise more optimistic results on survival.