Mucinous carcinoma of anal duct origin presenting clinically as a vaginal cyst

The vast majority of vaginal submucosal cysts are benign lesions. Primary malignant tumors of the vagina are infrequent and most are mucosal lesions. A case is described in which an unusual neoplasm, anal duct carcinoma, presented clinically as a vaginal lesion. The importance of considering anal neoplasia in the differential diagnosis of cystic vaginal lesions is noted.