Endoscopic ultrasonography of solitary rectal ulcer syndrome.

Solitary rectal ulcer syndrome (SRUS) is an uncommon poorly understood benign disorder of defecation. SRUS may simulate other disorders such as inflammatory bowel disease andneoplasms. Histopathological analysis forms the cornerstone of diagnosis for SRUS.Key histological features include fibromuscular obliteration of the lamina propria with splaying of the muscularis mucosae upward between the crypts, thickened mucosa, and glandular distortion [1]. Endoscopic ultrasonography (EUS) can be useful in the evaluation of SRUS. The characteristic findings are thick hyperechoic submucosa and thick hypoechoic muscularis propria with an intermediate hyperechoic layer. Linear EUS imaging shows a transition zone where the first interface layer and the muscularis mucosae disappear, and the submucosa gradually becomes thicker. The presence of an interface between the two muscular layers and between the muscular layer and the submucosa rules out malignant infiltration [2]. The hyperechoic band in the muscularis propria in SRUS has been attributed to a fibrous septum while the hyperechoic submucosa is due to a fibrotic lamina propria [3]. A 65-year-old man presented with a history of bleeding per rectum and straining at stool for 6 months. Sigmoidoscopy showed a large ulcer in the posterior rectal mucosa approximately 8cm above the anal verge (●" Fig.1;●" Video 1). Biopsies were sent for histopathological examination and a linear EUSwas performed. Linear EUS of the anal canal revealed normal thickness of the anal sphincters, but there was thickening of the submucosa as Fig.1 Sigmoidoscopic view showing a large ulcer in the posterior rectal mucosa. Fig.2 Linear endoscopic ultrasonography (EUS) images showing: a thickening of the submucosa and muscularis propria; b,c the solitary rectal ulcer in an otherwise normal rectum and the transition zone; d a hyperechoic layer in the thickened hypoechoic muscularis propria. Cases and Techniques Library (CTL) E76