Solitary ‘rectal’ ulcer syndrome in the sigmoid colon

Abstract

A 70-year-old woman underwent a repair of rectovaginal fistula with formation of an end colostomy in June 2005. This was complicated by repeated episodes of intra-abdominal sepsis, which were eventually resolved by completion proctectomy 2 years later. The colostomy functioned well after the operation although she reported having to evacuate formed stool manually from within the stoma. There was no stomal prolapse. She presented in December 2008 with diarrhoea and occasional, but significant bleeding from the colostomy. At colonoscopy (via the colostomy), a multi-lobed polypoid mass occupying a third of the lumen was observed in the sigmoid colon, 4–5 cm proximal to the stoma opening (Fig. 1). A well-demarcated liner ulcer was observed just distal to the lesion. The histology from the biopsy specimen from the site revealed glandular distortion, accompanied by proliferative smooth muscle fibres in the lamina propria (Fig. 1), suggesting fibromuscular proliferation and consistent with diagnosis of solitary rectal ulcer syndrome. Colonoscopy was otherwise normal with no evidence of diverticulosis. The patient was treated conservatively with bulking laxatives and advice to avoid digitation of the colostomy. Polypoid lesion and underlying ulceration as seen at colonoscopy (top). Corresponding histological findings of disturbed mucosal architecture, fibrosis of lamina propria and proliferation of muscularis mucosa (2a, H&E, original magnification ×40; 2b, H&E, original magnification ×100). Solitary rectal ulcer syndrome (SRUS) is an uncommon clinical entity with distinct clinical presentation and endoscopic and histopathological appearances [1,2]. Patients often present with mucous discharge, rectal bleeding, and tenesmus or anorectal pain. Endoscopic appearances vary from discrete ulceration, usually on the anterior abdominal wall to polypoid lesions. Twenty-five per cent of SRUS may be polypoid, 18% show mucosal erythema only and 30% are multiple. The differential diagnosis includes malignancy, inflammatory bowel disease, colitis cystica profunda and infectious causes. In view of this, histological confirmation is mandatory [3]. The typical histological features include fibromuscular obliteration, where lamina propria is replaced with smooth muscle and collagen, leading to hypertrophy and disorientation of muscularis mucosa and regenerative changes, with distortion of crypt architecture. The aetiology is not known but may involve a number of mechanisms. Ischaemic injury from pressure of the impacted stool and the local trauma due to repeated self-digitation may be contributing factors. Although originally described in the rectum, the endoscopic and histological features typical of SRUS have been reported in the proximal colon and ileum, associated with a prolapsing stoma. The unique feature in this patient was the lack of stomal prolapse. The appearances of a polypoid lesion may be mistaken for malignancy and histological confirmation is required particularly as SRUS may be present in association with malignancy. Management of SRUS should focus on improvement of patient’s symptoms. Patient education and behaviour modification (avoidance of self-digitation and the use of bulk laxatives) are the first steps in the treatment of SRUS. In patients whose symptoms are resistant to those conservative measures, a more organized form of behavioural therapy such as biofeedback are an option [4]. Topical treatments using sucralfate or 5-aminosalicylate enemas have been reported, anecdotally, to be of some benefit [5]. Surgery remains an option for patients not responsive to conservative measures and biofeedback.