Soft-tissue malignant fibrous histiocytoma (high-grade undifferentiated pleomorphic sarcoma) arising in a desmoid tumor in a patient with Milroy's disease

In summary, we present a case of an extremely high-grade undifferentiated pleomorphic sarcoma arising in a desmoid tumor, in a patient with chronic lymphedema. The case reinforces the need for aggressive intervention when a new mass develops in the region of a preexisting lesion. While this case is extremely unusual, such a strategy will encourage a timley and accurate diagnosis on which appropriate treatment may be based.