Background: Rectus muscle endometriosis is a rare entity. Though it occurs after previous surgeries, it can also occur in patients without scar. A differential diagnosis of extra-pelvic endometriosis must be kept in mind when women of reproductive age presents with mass abdomen which becomes painful during menstruation. CT/MRI can detect lesions and surgical excision remains the definitive treatment.
Case report: We present a case of a 30 year old, P2L2A1, with previous normal deliveries who presented with swelling over left iliac fossa which was painful during menstruation. CECT done showed endometriosis over rectus muscle. She underwent excision of the mass, which showed features of endometriosis in histopathology. She was on followed up for 2 years with no features of recurrence.