Angiosarcoma arising in a lymphedematous abdominal pannus with histologic features reminiscent of Kaposi's sarcoma: report of a case and review of the literature

Background  Despite common endothelial origins, angiosarcoma and Kaposi's sarcoma are clinically and histologically distinct vascular proliferations. The development of angiosarcoma in a chronically edematous abdominal pannus is extremely uncommon. Similarly, tumors with the combined histologic features of angiosarcoma and Kaposi's sarcoma have rarely been described. Methods  We reviewed the literature on angiosarcoma arising in a lymphedematous abdominal pannus and evaluated an 81‐year‐old morbidly obese woman who had profound, long‐standing edema of the lower abdominal wall in which an aggressive vascular tumor developed. Results  Three clinically similar cases were identified in the literature. All patients were women who generally experienced rapid disease progression. In addition, in our patient, sequential cutaneous sampling from different lesional sites demonstrated disparate histologic changes, ranging from those of classic Kaposi's sarcoma to high‐grade angiosarcoma, to areas with combined features of the two tumors. A polymerase chain reaction performed on lesional tissue was negative for human herpesvirus‐8 DNA. Conclusion  It is important to note that angiosarcoma may develop in the abdomen in association with chronic lymphedema, as demonstrated by the cases noted in this report. In addition, our case highlights the difficulty in differentiating histologically angiosarcoma from Kaposi's sarcoma in some situations, and demonstrates the value of close clinicopathologic correlation and sequential tissue sampling in evaluating problematic cases.