Perianal endometrioma: report of five cases.

One of the gynecologists' commonest findings at pelvic laparotomy is endometriosis. Despite the fact that the presence of endometrial tissue in ectopic locations is commonplace, the finding of a perianal endometrioma is no more than a surgical curiosity. Very few cases have been reported. The present report describes five such verified cases. Interestingly enough, only two of the five cases were diagnosed preoperatively. The pathogenesis of endometriosis has been, and continues to be, controversial. The prevailing theories include 1) transtubal regurgitation of menstrual blood, 2) the coelomic metaplasia doctrine, 3) lymphatic dissemination, and 4) hematogenous spread. Pathologically the lesions may vary grossly from red-blue to yellowish-brown implants, ranging in size from microscopic to 1-2 cm in diameter. The definitive histologic diagnosis requires two of the following three features-glands, stroma, and hemosiderin pigment. The clinical manifestations depend upon the functional activity of the involved tissue and may range from an asymptomatic mass to the classic presentation of a mass increasing in size and becoming acutely painful during menstruation but subsiding in size and decreasing in tenderness between menstrual periods. These protean manifestations are readily illustrated by the cases presented. Anatomically the lesions are usually found in old episiotomy scars. Because these lesions are usually readily accessible, and because their exact nature is frequently not known preoperatively, the treatment of choice is local excision. Complementary hormonal therapy has been suggested, but the value of such treatment is not yet proven. Ovarian ablative therapy is also considered.