INTRAABDOMINAL DESMOPLASTIC SMALL ROUND-CELL TUMOR WITH EXTENSIVE EXTRA-ABDOMINAL INVOLVEMENT

Intra-abdominal desmoplastic small round cell tumor (DSRCT) is a recen tly described, rare neoplasm that usually occurs in male adolescents, has a poor prognosis, and displays a typical clinicopathological profi le. This aggressive neoplasm exhibits a predominately intra-abdominal serosal pattern, with frequent pelvic extension, less frequent retrope ritoneal involvement, and rare pulmonary and mediastinal spread. We re port on the autopsy findings of a 9-year-old male who presented with a biopsy-proven DSRCT involving the abdomen, retroperitoneum, and scrot um and additional radiologic studies suggesting vertebral, hepatic, an d mediastinal involvement. Post-mortem examination performed 10 months after presentation confirmed the initial radiologic findings and demo nstrated extensive pleural and pulmonary metastases and, for the first time, direct evidence of bone marrow involvement. This tumor exhibite d the typical immunophenotype previously reported for DSRCT, namely mu ltidirectional expression of epithelial, neural, and muscular markers.