Cutaneous angiosarcoma arising in massive localized lymphedema of the morbidly obese: a report of five cases and review of the literature.

A significant proportion of angiosarcoma arises in the setting of chronic lymphedema, often following surgery for breast carcinoma (Stewart-Treves syndrome). Massive localized lymphedema (MLL), a relatively recently described and rare pseudotumor most often occurring in morbidly obese patients, is thought to be the result of derangements in lymphatic drainage secondary to excessive adipose tissue. Only a very small number of cases of angiosarcoma have been reported in patients with MLL. We reviewed the clinical and pathological features of five patients with angiosarcoma arising in this unusual clinical setting. The tumors arose in three women and two men, who were in the age range from 36 to 81 years (median: 52 years). All patients were or had recently been morbidly obese (mean body mass index = 47.2 kg/cm(2) ; range:37.6-68.5 kg/cm(2) ) and had long-standing soft tissue changes of MLL. The tumors arose in the thigh (two cases), lower leg (two cases) and abdomen/proximal thigh (one case) and ranged from 6 to 28.5 cm in size (mean: 15.9 cm). All tumors were conventional high-grade angiosarcomas and microscopically exhibited an admixture of vasoformative, spindled and epithelioid features. Microscopic changes of MLL, including dermal fibrosis, expansion of interlobular fibrous septa and lymphangiectasia, were identified in all cases. Clinical follow-up (four cases; mean: 13.8 months; range: 2-32 months) showed one patient to be dead of disease, one patient to be dead from therapy-related complications and two patients to be alive without disease. One case was too recent for meaningful clinical follow-up. We conclude that lymphedema secondary to obesity should be recognized as a significant risk factor for the development of angiosarcoma. The clinical and pathological features of angiosarcoma arising in this distinctive clinical setting appear to be identical to those of other lymphedema-associated angiosarcomas. With the continuing epidemic of obesity in Western societies, the incidence of obesity-related angiosarcoma is probably to increase. Consequently, it is critical that lymphedematous areas in obese patients be carefully examined for clinical evidence of early angiosarcoma, with the hope that timely diagnosis may lead to improved patient outcome.