Umbilical endometriosis: a rare diagnosis in plastic and reconstructive surgery [2] Perforating hemorrhagic (chocolate) cysts of the ovary [3] Endometriosis-associated infertility [4] A case of umbilical endometriosis: Villar's nodule [5] Umbilical hernia masking primary umbilical endometriosis -a case report [6] Primary umbilical endometriosis. Case report and discussion on management options [7] Primary Umbilical Endometriosis: Unusual and Rare Clinical Presentation [8] Surgical scar endometriosis after cesarean section: a case report [9] Primary umbilical endometrioma: a rare case of spontaneous abdominal wall endometriosis [10] Atypical clinical presentation of primary umbilical endometriosis [11] Cutaneous endometriosis [12] Umbilical endometriosis [13] Primary umbilical endometriosis: a cause of a painful umbilical nodule [14] Menstruating from the umbilicus as a rare case of primary umbilical endometriosis: a case report [15] Endometriosis of the umbilicus [16] Endometriosis of the umbilicus