Frequent observations have been made in the literature, not only that carcinoma of the small intestine is a rare lesion but that it is a difficult one to diagnose. It is evident, from reports on malignant lesions of the small intestine, that many months may ensue before sufficient symptoms and signs make their appearance to cause the patient to present himself to a physician for proper evaluation; even then, the most careful scrutiny is required to demonstrate the tumor. Roentgen diagnosis, too, has been shown to be quite difficult at times. 1 The unusual occurrence of an internal fistula developing from a primary carcinoma of the ileum is presented in the following case. REPORT OF A CASE A. K., a white woman aged 62, had a total hysterectomy with bilateral salpingo-oophorectomy in April 1949 for adenocarcinoma of the fundus uteri. In February 1950, she returned to the hospital with a