Congenital anal duplication: a cause of para-anal sinus.

Four cases of recurring para-anal sinus originating, it is suggested, as congenital duplication of the anal canal, are described. The diagnosis depends upon the finding of columnar mucus-secreting epithelium in a sinus track which does not communicate with the bowel lumen. The sinus may or may not penetrate the levator ani muscle. Treatment should be by excision of the sinus, rather than by laying it open into the anal canal. If the sinus is superficial, the latter operation will result only in delayed healing and prolonged convalescence, but if it runs deep, there is a danger of causing incontinence or an extra-sphincteric fistula. Untreated lesions may eventually be the site of malignant change. This complication was not encountered in the present series.