COLORECTAL ADENOCARCINOMA AS A 2ND MALIGNANT NEOPLASM FOLLOWING WILMS-TUMOR AND RHABDOMYOSARCOMA

Colorectal carcinoma is one of the most common primary malignancies in adults and occurs in older patients after pelvic radiation. It is rar e in children and young adults. We report two cases of colonic adenoca rcinoma which were second malignant neoplasms following treatment for early childhood malignancies, One child had Wilms' tumor at 9 months o f age treated with preoperative radiation and surgery ne developed rad iation colitis and multifocal intestinal adenocarcinomas 42 years late r and died with abdominal carcinomatosis. The second child had retrope ritoneal embryonal rhabdomyosarcoma at age 1 year and was treated with preoperative radiation, surgery, and chemotherapy, At age 2 years he had radiation colitis; at age 11 years he had rectal adenocarcinoma as sociated with adenomatous polyps, focal adenomatous change and radiati on colitis. Immunohistochemical studies revealed p53 positivity in bot h adenocarcinomas and in adenomas from the second patient, suggesting that p53 mutation was involved in carcinogenesis. The history of high- dose radiation in early childhood and the muitifocal lesions suggest t he adenocarcinomas in both patients were second malignant neoplasms, w ith associated reactive and benign neoplastic and premalignant lesions well documented in one case. These two cases document the phenomenon of early onset of adult type tumors in survivors of childhood cancer a nd emphasize the need for continued clinical evaluation of patients at risk for second malignant neoplasms. (C) 1996 Wiley-Liss, Inc.