A case of sigmoidouterine fistula detected by transvaginal ultrasonography

Abstract

An 80-year-old woman, 2 G 2 P, with macrohematuria came to this institution for treatment. On pelvic examination, the uterus was palpated slightly large for her age, slight tenderness and resistance were noted at the uterine corpus, and the adnexa and parametrium were soft. The entire abdomen, including the Douglas pouch and pelvic bottom, were also soft. Examination a the speculum revealed swelling of the vulva and vagina and blood oozing from the entire vaginal wall. There was also a small amount of purulent discharge at the cervical canal. Transvaginal ultrasonography (TVUS) showed the uterine corpus to be small and found no adnexal or pelvic mass. However, the entire uterine cavity was hyperechoic, and these signals were passing through the myometrium near the fundus and ended in a cup-shaped configuration. These features were consistently confirmed on later repeated TVUS examinations. On further interview, the patient disclosed that the had had continual diarrhea and fecal discharges from the vagina for close to one month. The cytology of the smears from both the uterine cervix and cavity were negative, but purulent content was found in the endometrial biopsy specimen. Computed tomography and magnetic resonance imaging revealed no pathologic findings, but a colonic mass lesion adjacent to the uterus was observed although the fistula could not be identified. Innumerable diverticula in the colon and the outlines of barium spillage from the colon were demonstrated on barium enema examination. Colonic fiberscopic examination confirmed the intact colonic mucosa. Of the tumor markers, CA 19-9 and SCC values were normal, while CEA level was elevated (9.8 ng/ml). Surgery revealed a fistula that was perforated from the bottom of the sigmoid diverticulum through the uterine myometrium, and into the uterine cavity. The features of fistulas delineated by the continuous high-echoic signals on TVUS were identical with these pathological findings. The microbubbles of bowel gas in fecal discharges were deemed to be the cause of high echogenicity. These TVUS findings were repeatedly confirmed on later evaluations. A diagnosis of a sigmoidouterine fistula on TVUS should, therefore, be considered when there is fecal discharge. TVUS thus provided crucial and reliable findings of uterine fistula and should warrant use in managing colonic-uterine fistula. The postoperative course was uneventful. CEA concentration decreased to 3.4 ng/ml; cut-off value was 5 ng/ml.