Composite tumor consisting of dermatofibrosarcoma protuberans and myxoflbrosarcoma

Abstract

A unique case of a composite tumor consisting of dermatofibrosarcoma protuberans and low-grade myxofibrosarcoma is described. The myxofibrosarcoma component formed 70% of the lesion volume. Both components protruded above the skin, and equally both infiltrated the subcutaneous tissue in the base of the lesion. The interface between them was mostly sharp but some small areas of gradual transition were also seen. Beside fibrosarcoma arising in the dermatofibrosarcoma protuberans, myxofibrosarcoma seems thus to be another possible manifestation of the change into a more malignant tumor rarely seen in the dermatofibrosarcoma protuberans.

Myxofibrosarcoma in the skin

“…A myxofibrosarcoma initially mistaken for a pleomorphic hyalinizing angiectatic tumor (PHAT) has recently been reported, 8 but the ectatic hyalinized vessels and bizarre nuclear atypia that typify PHATs were not present in any of the cases we encountered. Dermatofibrosarcoma protuberans (DFSP), particularly the myxoid variant, has also been reported to mimic and even merge with myxofibrosarcoma, 18 but none of the cases in our series significantly resembled DFSP clinically, histopathologically or immunophenotypically. Myxoid DFSP generally lacks the multilobular growth pattern, curvilinear vessels and cytoatypia encountered in myxofibrosarcoma 19 …”

Dermatofibrosarcoma protuberans – An Update

“…It is also possible that these malignant features are selected out by repeated recurrences [12]. Myxoid differentiation appears to be a further subtype of DFSP [28, 29].…”