Imaging description

A teenage boy presented with increasing abdominal girth and diffuse abdominal pain. Clinical exam revealed a palpable mass in the lower abdomen and pelvis. A CT scan demonstrated a large, predominantly solid mass in the pelvis with evidence of mesenteric and nodal metastases (Fig. 53.1). A biopsy confirmed the suspected diagnosis of a desmoplastic small round cell tumor.

Importance

A desmoplastic small round cell tumor is a very aggressive type of soft tissue sarcoma, which typically presents in adolescent white boys. Ninety percent of the affected patients are males and 85% are white. The tumor shows clinical and imaging characteristics similar to malignant ovarian cancers in women. It grows very fast and often remains unnoticed or misdiagnosed for a long time. When finally diagnosed, most tumors are very large and have already spread, leading to an overall dismal five-year survival rate of less than 15%. Treatment consists of aggressive surgical resection, chemotherapy, and sometimes irradiation. A complete surgical resection is the single most effective intervention to improve outcomes. Thus, an earlier diagnosis is critical to improve the prognosis of these patients.