ClinicalRadiology (1991) 43, 358-359 Case Report: Rectal Mucocoele Following Hartmann's Procedure M. F. CREAGH and T. Y. K. CHAN Department of Radiology, St Thomas' Hospital, London A post-surgical rectal stump normally secretes a small amount of mucus which is passed per rectum. An example of an unusually large collection of mucus (mucocoele) in a rectal stump is presented and the difficulties in diagnosis discussed. Creagh, M.F. & Chart, T.Y.K. (1991). Clinical Radiology 43, 358-359. Case Report: Rectal Mucocoele Following Hartmann's Procedure CASE REPORT A 59-year-old woman who was known to have papillary carcinoma of thyroid was admitted with spinal cord compression due to metastases at T7 and T8 levels. Despite radiotherapy and surgical decompression, the patient suffered irreversible loss of sensation below T10 level and spastic paraplegia. Six weeks later, she complained of acute abdominal pain. Plain radiographs showed free intra-peritoneal gas and subsequent laparo- tomy revealed stercoral perforation of a grossly dilated sigmoid colon. A Hartmann's operation was performed. The rectal stump was oversewn and replaced within the pelvis, and an end colostomy fashioned in the left iliac fossa. Two months post-operatively she developed a fluctuating pyrexia and lower abdominal tenderness. Ultrasonography demonstrated a retro- uterine fluid collection within the pelvis, 9 cm in diameter (Fig. 1). This collection was considered consistent with a pelvic abscess. Digital examination of the rectum led to the discharge of approxima- tely 500 ml of pus. The pyrexia resolved rapidly. Three weeks following release of this collection symptoms returned and a computed tomographic examination of the pelvis demonstrated a recurrence o f the retro-uterine collection (Fig. 2). Again rectal examina- tion released a quantity of turbid, mucoid fluid with prompt amelio- ration of symptoms. Thereafter, the patient complained of periodic discharge of mucus per rectum occurring approximately every 14 days. Vesico-rectal fistula was excluded by instillation of methylene blue dye into the bladder. Finally a water soluble contrast study of the rectal stump was undertaken to Fig. 2 - CT pelvis. A well circumscribed fluid collection lies posterior to the atrophic uterus. The bladder contains contrast. Bowel loops are seen anterior to the bladder. Fig. 1 -Ultrasonography in the sagittal plane demonstrating a large fluid collection in the pelvis. A balloon catheter is seen in the bladder anteriorly. Correspondence to: T. Y. K. Chan, Department of Radiology, St Thomas' Hospital, London SE1 7EH. Fig. 3 - Water soluble contrast enema per rectum shows a capacious rectal stump. The rectal folds are evident. There is no fistula or sinus. investigate the possibility of a communication with an extraluminal collection. It showed a very capacidus rectum which conformed in shape and size to the collection demonstrated on computed tomography (Fig. 3). The patient has since had regular digital evacuation and remains free of perineal complaint. DISCUSSION Hartmann's procedure is the operation of choice for perforated diverticulitis of the colon. The outcome