Malignant colo-jejunal fistula--a rare internal fistula.

Small bowel fistula can be classified as internal, external and mixed. In internal gastro-intestinal fistulas a communication exists between segments of intestine or with any other hollow viscus, whereas in external gastro-intestinal fistulas intestine communicates with skin of abdominal wall. The mixed variety involves both internal and external communications often through an abscess cavity. Most of small intestinal fistulas (75-80%) occur as complication following surgery; rest (20-25%) includes spontaneous type.13 The principal causes of entero-enteric fistula in order of frequency are Crohn’s disease, diverticular disease, colo-rectal malignancy, radiation enteritis, tuberculosis and actinomycosis.2 The internal gastrointestinal fistulas include gastro-colic, duodeno-colic, entero-colic, entero-enteric, colo-vaginal and colo-vesical. Most common ileo-colic fistula is to sigmoid colon.1-3 Eighty five years female presented with constipation for three months followed by loose watery stools, 4-6 per day, small quantity, with crampy pain and streaky blood occasionally. She used to pass stool after 10-15 minutes taking oral feeds. Her weight was 38 kg, had mild pallor and was dehydrated. Hemoglobin was 7gm% with dimorphic anemia. Serum biochemistry was normal. On small bowel barium studies, there was rapid passage of contrast from small bowel and small amount of barium was noted in sigmoid colon. Barium enema studies showed a narrowing at recto-sigmoid junction with passage of contrast directly to jejunal loops from sigmoid colon (Fig. 1). Colonoscopy revealed a growth at rectosigmoid junction which was proved to be adenocarcinoma on histopathology. CT scan for abdomen showed a thickened wall of sigmoid colon with infiltration in mesentery and loops of small bowel (Fig. 2). She was advised surgery and chemotherapy but refused.