Cutaneous metastatic adenocarcinoma arising from a malignant sacrococcygeal teratoma in an adult.

We present a patient with cutaneous metastasis caused by an adenocarcinoma arising from a malignant teratoma. A 37-year-old woman seen for the complaint of swelling in the genital region also complained of a draining mass in her gluteal region present since birth. Physical examination showed marked edema in the labia majora, multiple hyperkeratotic papules in the left labium majus, and erythema, induration, and swelling in the left femoral and inguinal regions. A soft tumor that exhibited sinus tracts was palpated in the left gluteus. Excision of the gluteal tumor revealed a teratoma. Vulvar skin biopsy confirmed a mucinous adenocarcinoma which had derived from this teratoma. A tumor that arises from pluripotent germ cells, teratoma rarely shows malignant transformation. The patient presented is a rare example of a cutaneous metastasis originating from a congenital sacrococcygeal teratoma in an adult.