[Myxofibrosarcoma associated with anetoderma]

Association of malignant cutaneous tumor and secondary anetoderma is rare. Secondary anetoderma in myxofibrosarcoma has not been described to date. We report a case below.

A 80-year-old woman presented with a 40 x 40 mm, round, flesh-colored lesion on her left buttock. Physical examination showed a soft, protuberant lesion, without firm underlying subcutaneous mass. Pathologic examination of the surgical specimen revealed a myxofibrosarcoma, with focal loss of elastic fibers in the overlying dermis. There was no evidence of systemic involvement. One year later, she developed a recurrent tumor at the same site, with similar clinical presentation, which was treated by broad excision.

Secondary anetoderma is usually seen in association with cutaneous infections and benign skin tumors. An anetodermic presentation of myxofibrosarcoma has not been reported to our knowledge. Myxofibrosarcoma (formerly referred to as myxoid malignant fibrous histiocytoma) is characterized by an abundant myxoid background in at least one half of the tumor. The tumor recurs in almost two-thirds of cases and metastasizes in one-fourth. Our case confirms that a unique, acquired anetodermic lesion can reveal a malignant tumor. A large deep biopsy should be performed systematically when this variety of anetoderma is observed.