Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 47 2 2009 04 15 154 156 EN Loabat Geranpaye Department of Surgery, Sina Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Mohsen Fadaei-Araghi Department of Surgery, Sina Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Shirin Irani Department of Surgery, Sina Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Behnam Shakiba Department of Surgery, Sina Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. 2015 09 28 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. https://acta.tums.ac.ir/index.php/acta/article/view/3564 https://acta.tums.ac.ir/index.php/acta/article/download/3564/3540