**25. Histological features of spontaneous umbilical endometriosis**

Endometriosis of the umbilicus in the absence of previous caesarian section or hysterectomy is described as spontaneous endometriosis and it is caused by lymphatic dissemination of endometrial tissue, through lymphatic vessels extending between pelvis and umbilicus. Umbilical endometriosis may recur after surgical resection (Chen, 1998).
