Intraabdominal desmoplastic small cell tumor. Report and discussion of five cases

Intraabdominal desmoplastic small cell tumor is a rare malignancy that has only recently been described. In the adult population, it is usually seen in young males. The tumor appears to arise as a dominant mass or masses in the abdominal cavity, particularly in the pelvic region, without a clear visceral origin. Multiple small tumor nodules may be found attached to the peritoneal surface. Visceral metastases occur late in the clinical course, ultimately leading to the patient's death. Five young adults with intraabdominal desmoplastic small cell tumors were treated with aggressive chemotherapy.

Charts of five patients treated between 1990 and 1995 were reviewed. The diagnosis of desmoplastic small cell tumor was made on the basis of typical clinical and radiographic findings, light microscopy showing hyperchromatic cells surrounded by a desmoplastic stroma, and immunohistochemistry demonstrating markers of epithelial and mesenchymal differentiation. Patients were treated with aggressive combination chemotherapy consisting of alternating regimens similar to those used as testis cancer salvage therapy.

Four of the five patients demonstrated a partial response to chemotherapy. Two of the responding patients had surgery with the intent of removing all residual disease, but this was successful in only one case. All patients have died from their cancer.

Intraabdominal desmoplastic small cell tumors are sensitive to combination chemotherapy. It appears that treatment offers good palliation and may prolong survival in isolated cases. However, even the patients managed with the most aggressive medical and surgical approaches are not cured and ultimately die of their disease.