Recurrent dermatofibrosarcoma protuberans with myxoid and fibrosarcomatous changes paralleled by loss of CD34 expression.

A 38-year-old woman complained of recurrent nodules on her anterior chest wall. She noticed the first nodule at the age of 12 and has since undergone surgical removal a total of 31 times. Finally, wide resection of parts of the rib cartilage and sternum and chest wall reconstruction were required. Histopathological examination of a series of surgical specimens were reevaluated. Immunohistochemical staining of the tumors by anti-CD34 antibody provided a definite diagnosis of dermatofibrosarcoma protuberans (DFSP). A noteworthy result was that her DFSP did not always express CD34; the recurrent tumors with myxoid and fibrosarcomatous changes lost their CD34 expression.