A 14-week-old female infant presented with an irreducible rectal prolapse and a large polypoid tumor at the tip of the prolapsed mucosa. The tumor and prolapsed rectum were resected. Four weeks after the operation, profuse rectal bleeding occurred and a second similar tumor was diagnosed by endoscopy in the sigmoid colon. Laparotomy, rectosigmoid resection, and endorectal pull-through were performed. At operation, the serosal surface showed ragged polypoid lesions and an abnormal angiomatous vascularization. The postoperative course was uneventful. The histology suggested a congenital mucosal malformation. This pathology is unique in our experience and we have been unable to find anything resembling it in the literature. At age two years a Sertoli cell tumor developed in the girl with pubertas precox and a recurrent colonic polyp of the Peutz-Jeghers type.