A focus of endometriosis may be found in the skin or subcutaneous tissue. Its presence is often associated with endometriosis elsewhere.


Clinical features:

(1) The color may be any combination of blue, red or brown.

(2) The nodule may be tender or painful. It may enlarge during menstruation.

(3) The lesion may be cystic or solid.

(4) A cutaneous fistula may occur and drain blood during menstruation.

(5) The woman may have a history of endometriosis.


Common locations:

(1) umbilicus

(2) surgical scars (Bartholin cyst surgery, perineal lacerations, Cesarean section site, laparoscopy site, abdominal scar)

(3) vulva or perineum


Surgical excision will show histologic features of endometriosis, with glands, stroma, fibrous tissue, hemosiderin and blood.


Differential diagnosis:

(1) cutaneous metastasis

(2) skin adnexal tumor

(3) epidermoid cyst

(4) lipoma

(5) scar granuloma


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