An umbilical nodule due to endometriosis.

Sir, Endometriosis is common, and extrapelvic deposits may occur in up to 12% of affected women. Cutaneous endometriosis is rare, usually appearing in surgical scars or following procedures such as hysterectomy, caesarean sections, episiotomy and laparoscopy. It is probably the result of implantation of viable endometrial cells or their transport via vascular channels. Umbilical endometriosis is rare, with an estimated incidence of 0.5–1% of all patients with endometrial ectopia (1). It can occur after surgery but is generally spontaneous. There is an important differential diagnosis, which includes malignant melanoma, and a metastatic deposit from a systemic malignancy, in particular a gastrointestinal primary tumour, should be considered. We report here a case of umbilical endometriosis in a young woman whose past medical history was unremarkable and highlight how important an accurate history can be in determining correct diagnosis.