Episiotomy endometrioma masquerading as peri-anal sepsis: surgeons beware!

A 34-year-old woman with peri-anal pain and swelling was operated in the emergency setting assuming a diagnosis of a perianal abscess. No pus was revealed. Later magnetic resonance imaging (MRI) suggested induration and a mass effect in the peri-anal region. Examination under anaesthesia was repeated which revealed a mobile but firm mass. Histology from trucut biopsies diagnosed it as a peri-anal endometrioma arising from an episiotomy scar. Peri-anal endometrioma can rarely developin episiotomy scars and can be easily mistaken as an abscess by junior surgeons.