napkin ring lesion
Aetiology Large adenocarcinoma, especially in the left colon, which may obstruct the faecal flow, resulting in pencil-thin stools. The lesion may be partially mimicked by concentric amebomas in Entamoeba histolytica granulomas, by exuberant submucosal fibrosis in Crohn’s disease, by stenosing fibrotic stages of diverticulosis coli, and may occur in small intestinal adenocarcinoma
napkin ring lesionApple core lesion Radiology A pattern of GI constriction caused by mucosal erosion and stenosis with 'shouldering' of the margins, corresponding to an exophytic encircling mass in the colonic lumen, usually corresponding to a large adenocarcinoma, more in the left colon;
the mass may obstruct fecal flow, inducing pencil-thin stools, and be partially mimicked by concentric amebomas in Entamoeba histolytica granulomas, by exuberant submucosal fibrosis in Crohn's disease, in the stenosing fibrotic stages of diverticulosis coli, in an SCC arising in a dermoid cyst of the ovary with invasion of the muscularis of the rectosigmoid colon and in small intestinal adenoCA. See Squamous cell carcinoma.