Cutaneous Stewart-Treves lymphangiosarcomas represent a rare group of tumors characterized by a high grade of vascularization and by localization in an extremity with lymphedema. The multifocality and the localization makes these tumors eligible for treatment with isolated limb perfusion (ILP). ILP with tumor necrosis factor (TNF) and melphalan is a safe and highly effective procedure that can achieve limb salvage in ≥80% of all patients with nonresectable extremity soft tissue sarcoma or melanoma. In 10 patients with multifocal Stewart-Treves lymphangiosarcoma of the extremities, 16 ILPs with TNF plus melphalan were performed. All patients would have been candidates for exarticulation of the extremity. We observed an 87% overall response rate (complete and partial responses); one patient had a mixed response, and one patient did not respond to the therapy. In nine perfusions (56%), a complete response was achieved, and five perfusions (31%) resulted in a partial response. Limb salvage was achieved in eight patients (80%), with a mean follow-up duration of 34.8 months (range, 3 to ≥115 months). Regional toxicity was limited and systemic toxicity minimal to moderate, with no toxic deaths. Multifocal Stewart-Treves lymphangiosarcomas in extremities with chronic lymphedema can be successfully treated by ILP with TNF and melphalan.