Intra-abdominal desmoplastic small round cell tumor (IDSRT).

Intra-abdominal desmoplastic small round cell tumor (IDSRT) is a rare neoplasm that develops in the abdominal cavity in young people. We experienced a 27-year-old man who visited with ascites of unknown cause. Compression of the colon was found by barium enema examination. On colonoscopic examination, diffuse white elevated lesions, about 5 mm in diameter, surrounded by rubedo, so-called aphthoid lesions, were also observed. IDSRT was diagnosed by biopsy at laparotomy, and chemotherapy with cyclophosphamide, etoposide, doxorubicin, and cisplatin was performed. The tumors shrank temporarily (partial response), but subsequently grew in size again. The patient died during the second course of chemotherapy after relapse. We present one case report, together with a review of the literature.