Abstract
Endometriosis involves the growth of endometrial-like tissue outside the uterine cavity, with its manifestation in the rectus abdominis muscle being exceptionally rare and primarily observed in women with a history of abdominal surgeries. In this report, we present the case of a 42-year-old female with a medical history of two cesarean sections who presented with cyclical abdominal pain and a palpable mass in the right lower quadrant. An MRI scan of the pelvis revealed a lesion on the right lower quadrant of the abdominal wall, proximate to the previous Pfannenstiel incision. A percutaneous US-guided biopsy of the abdominal lesion was performed, and histopathology demonstrated the presence of endometrial glands and stroma, confirming the diagnosis of rectus abdominis endometriosis. She was submitted to a local wide excision with adequate margins of normal surrounding tissue and has remained free of recurrence for two years.