Two cases of Kaposi's sarcoma mimicking Stewart-Treves syndrome found to be human herpesvirus-8 positive.

Although angiosarcoma is the most frequent tumor arising in the clinical setting of chronic lymphedema, as in Stewart-Treves syndrome, Kaposi's sarcoma has also been reported in this setting, although rarely. We describe two women who developed Kaposi's sarcoma in the lymphedematous arm many years after surgery for breast cancer. Case 1 is a 92-year-old and Case 2 is an 81-year-old; they underwent left total mastectomy and axillary node dissection for infiltrating breast carcinoma in 1981 and 1982 respectively. At that time, neither patient received further treatment. Except for persistent lymphedema, both women did well until over fourteen years later when each noted the development of several purple asymptomatic plaques on the edematous arm. In both, the clinical diagnosis at the time of biopsy was angiosarcoma. However, histologic findings in both cases were typical for Kaposi's sarcoma. In addition, a nested polymerase chain reaction (PCR) for the detection of a 233bp segment of KSHV/HHV8 was performed on DNA extracted from the paraffin-embedded specimens and both cases were positive for this sequence. Histologic sections of both cases were also tested for KSHV by in situ hybridization and demonstrated a positive signal in the lesional cells in each case.