E‐Poster Presentations ‐ A4) Lower GI

A 24-year-old lady with good past health complained of persistent blood-less diarrhea for 3 months. The frequency was up to 6 times per day, and there was lower abdominal discomfort and significant weight loss. Lower abdomen was soft but distended on examination. Blood tests revealed microcytic, hypochromic anemia and raised inflammatory markers (CRP 40; ESR 71). Colonoscopy showed mild rectal inflammation only. Terminal ileum and colonic biopsies were unremarkable. Further imaging with CT enteroclysis showed a 6-cm right dermoid and a 9-cm left dermoid with air-fluid level. Fistulation to rectosigmoid junction was suspected. Repeated sigmoidoscopy showed a hair-like protrusion and suspected fistula opening at 10 cm above anal verge. Open right ovarian cystectomy, left salpingooophorectomy, and anterior resection of rectum with defunctioning ileostomy was performed. Intraop confirmed central 3-mm fistulation over left dermoid. Pathology was benign mature cystic teratoma. Patient had no more diarrhea. Closure of stoma was arranged. Fistula formation by dermoid occurs in< 1%of cases. Symptoms depend on site of fistula. Bladder is the commonest site, followed by colon. Pathogenesis is not always malignant. In a case series (n = 17) of dermoid with fistulation, only 4 were due to direct malignant infiltration. Remaining 13 cases were due to inflammation. Physicians should be aware of this uncommon but potentially treatable entity when encountering chronic diarrhea.