Invasive cancer in a diminutive rectal polyp amidst internal hemorrhoids detected by rectal retroflexion.

A diminutive rectal polyp amidst internal hemorrhoids, detected by rectal retroflexion during colonoscopy, was shown to harbor invasive rectal adenocarcinoma by colonoscopic biopsy. Initially this lesion had appeared to be a relatively innocuous prominent anorectal mucosal fold and was recognized as a diminutive polyp only after careful rectal retroflexion during colonoscopy. This report emphasizes that lesions just above the anorectal junction with atypical endoscopic features for internal hemorrhoids should be carefully examined at rectal retroflexion and that polyps or suspicious lesions amidst internal hemorrhoids identified during colonoscopy should be snared or at least biopsied, even if small. This case report also illustrates how easily an early cancer in a diminutive colonic polyp can be missed when in difficult areas of colonoscopic inspection, such as behind a colonic fold or immediately above the anus.