RESUMEN
Perineal endometriosis with anal sphincter involvement is a rare occurence with only 11 reported cases so far. This is a case of a 32 year old woman presenting with cyclic perineal pain, abnormal uterine bleeding, and a history of episiotomy. On physical examination, a perineal mass was palpated. There was also finding of an endocervical polyp. Endoanal sonography revealed external anal involvement of the perineal mass. Surgical excision of the endometric mass together with part of the external anal sphincter was carried out. The procedure was followed by anal sphincter reconstruction in an "overlapping" fashion. A fractional curettage with cervical polypectomy was also done. Histopathologic tests confirmed endometriosis and endocervical polyp. She was then given mefenamic acid for the pain. Since then, the patient has been asymptomatic. There were no complications and no anal incontinence. Awareness of the occurence of this rare type of extrapelvic endometriosis is important in the management of patients presenting with perineal pain occurring during menses.