What is the clinical presentation of angiosarcoma arising in chronic lymphedema?

This rare tumor, also called Stewart-Treves syndrome, arises as cutaneous and subcutaneous firm, coalescing, violaceous nodules on a background of nonpitting edema, often in the inner aspect of the upper arm. It occurs on average 10 years following mastectomy and lymphadenectomy (range 1 to 30 years). It is less commonly associated with filarial, congenital, traumatic, or idiopathic lymphedema.

Hallel-Halevy D, Yerushalmi J, Grunwald MH, et al: Stewart-Treves syndrome in a patient with elephantiasis, J Am Acad Dermatol 41:349–350, 1999.