Spontaneous Endometriosis of the Abdominal Wall

Abdominal wall endometriosis, the commonest type of extra-pelvic endometriosis, may rarely develop spontaneously in the absence of prior surgical scar. We aim to report 3 cases with this unique characteristic, two of them with a diagnosis of unusual development of umbilical endometriosis and one with inguinal endometriosis, from the perspective of a general surgeon. Because of the potential pitfalls in its diagnosis, endometriosis should be emphasized in the differential diagnosis of abdominal wall masses.