Intra-abdominal desmoplastic small round cell tumor in children: a clinicopathologic study.

Desmoplastic small round cell tumor (RCT) is a relatively newly recognized neoplasm. It has a very distinct morphologic and high-grade polyphenotypic expression with a very poor prognosis. It is commonly seen in adolescent boys. We describe two cases of intra-abdominal desmoplastic small RCT in young girls (5 and 11 years of age). In both cases, the exact origin of tumor in the abdomen could not be established. Histopathologic examination of the biopsy specimens showed distinct desmoplastic stroma and coexpression of various epithelial, neural, and muscle markers. These two patients were treated primarily by debulking surgery followed by adjuvant chemotherapy (RCT II protocol). One of the two had a stable disease while the other had a progressive disease while on treatment. Thus our findings support the diverse histogenesis of this tumor and its poor prognosis.