Radiation damage to the ileum, first mentioned by Walsh (21) in 1897, is of two types: acute, usually observed during the course of irradiation or just following it, and late, generally developing six months to five years after therapy. Occasional cases are seen much later than five years, when they present diagnostic problems because of obscure bleeding, partial small-bowel obstruction, or vague symptoms suggesting psychoneurosis as a predominant feature. Sometimes recurrent neoplasm has been mistakenly diagnosed. Perforation of the ileum has been an occasional complication. The primary disease for which radiation was given in such cases was most often carcinoma of the cervix uteri, though testicular tumors (2, 5) (treated for involvement of retroperitoneal nodes or prophylaxis of this area), carcinoma of the corpus uteri (15, 16, 20, 24), carcinoma of the colon (10), carcinoma of the ovary (14, 20), and plasma-cell myeloma of the ileum (18) are also among the initial conditions. It might be anticipated ...