Umbilical endometriosis, also called Villar nodule, is an extremely rare type of endometriosis, with an incidence of 0.5% to 0.1% among women with extragonadal or external endometriosis.1 The urachus, a vestigial structure arising from the anterior bladder wall, is progressively destroyed with advancing age, but destruction does not occur in approximately 1 in 5000 individuals.2 This report describes a case of umbilical endometriosis that developed in the absence of previous abdominal or uterine surgery.