Endometriosis outside the pelvic cavity is rare, but its most common extra-pelvic location is the abdominal wall, occurring most frequently after cesarean delivery. Fistula tracks through these lesions in the abdominal wall to the uterus are rare. However, a fistula between abdominal wall endometriosis to an endometrioma has not been reported. A 46-year-old multigravid woman presented with complaint of cyclical pain and bleeding from her cesarean delivery scar and pelvic pressure. Computed tomography revealed a complex, 16-cm left adnexal mass. Intraoperatively, a fistulous tract connecting a large endometrioma in the abdominal-pelvic cavity to the skin was noted and wide local excision of this track was performed in conjunction with aggressive surgical management of endometriosis throughout the pelvis. Pathologic analysis of the resected specimen confirmed the diagnosis. Although rare, endometrioma-cutaneous fistula should be included in the differential diagnosis of suspected abdominal wall endometriosis with concurrent adnexal mass for appropriate surgical planning.