Intramuscular endometriosis of the forearm: a case report.

Endometriosis is a disorder that commonly affects females of reproductive age and is defined as the presence of endometrial glands or stroma outside the uterine cavity. Patients typically present with cyclical pain during menses. Endometriosis can be characterized as endopelvic or extrapelvic depending on the sites involved. We report a case of a 40-year-old, right-hand-dominant, female who presented with a painful mass in her right proximal forearm. She was ultimately diagnosed with intramuscular endometriosis and underwent surgical excision.