Desmoplastic small round cell tumor of the abdomen

a 21-year old woman presented with a 2-month history of abdominal pain. the diagnostic work-up disclosed a 17-cm intraperitoneal mass. biopsy showed islets containing small round cells surrounded by abundant desmoplastic stroma. immunohistochemistry was strongly positive for desmin and weakly positive for vimentin and neuron-specific enolase. pathological diagnosis was intraabdominal round cell desmoplastic tumor. the patient underwent an intensive schedule of high-dose alkylator-based chemotherapy, the p6 protocol, designed by the pediatrics division of the memorial sloan-kettering cancer center. she had a partial response and subsequently underwent resection of the residual mass followed by high-dose chemotherapy with stem cell support. ten months later, the patient had disease progression and is currently receiving second-line chemotherapy.