2. Histologically proven diffuse peritoneal or retroperitoneal tumor from the following histologies: adenocarcinoma of the gastrointestinal tract, desmoplastic round cell tumor, late stage neuroblastoma, ovarian germ cell, sarcoma, adrenocorticocarcinoma, Wilms', rhabdomyosarcoma. (target groups: desmoplastic small round cell tumor (DSRCT), neuroblastoma, and recurrent tumors). If tumors are outside the abdominal cavity, the tumors must be controllable.