Circumferential perianal pilonidal sinuses.

Two cases of recurrent perianal suppuration are described in which the underlying pathology is believed to be pilonidal sinus disease affecting the perianal skin directly. This has given rise to intersphincteric fibrosis and, in one case, a subcutaneous track almost completely encircling the anus. The pathogenesis of the condition and its possible relationship to previous surgery are discussed.