Stewart–Treves syndrome

Stewart–Treves syndrome is a lymphangiosarcoma, a rare disorder marked by the presence of an angiosarcoma (a malignant tumor of blood or lymph vessels) in a person with chronic (long-term) lymphedema. Although it most commonly refers to malignancies associated with chronic lymphedema resulting from mastectomy and/or radiotherapy for breast cancer, it may also describe lymphangiosarcomas that result from congenital and other causes of chronic secondary lymphedema. Lymphangiosarcoma arising from cancer-related lymphedema has become much less common with better surgical techniques, radiation therapy, and conservative treatment. The prognosis, even with wide surgical excision and subsequent radiotherapy, is poor.

Lymphangiosarcoma usually occurs many years following a mastectomy, usually between 5 and 15 years.

Cutaneous angiosarcoma can begin as a "spreading bruise" or a raised purple-red papule before progressing to tissue infiltration, edema, tumor fungation, ulceration, and even hemorrhage as tumor size increases. The second most frequent location is in a lymphedematous upper extremity secondary to radical mastectomy. This is known as the "Stewart Treves tumor". Lesions range in size from 3 to 6 cm on average, although untreated angiosarcomas can grow to 20 cm or more.

Severe persistent edema of an upper extremity is common in Stewart-Treves syndrome patients and is often the first sign. In patients who underwent a radical mastectomy, edema initially appears on the arm of the side operated on.

The edematous area spreads from the arm to the forearm and the dorsal side of the hand and fingers. Pain is initially absent, though skin distention may cause local discomfort. Recurrent erysipelas may occur in sites with long-standing chronic edema.

Stewart-Treves syndrome lesions often present as several reddish blue macules or nodules that may develop polypoid. Small satellite areas can form around these areas and become confluent, producing a growing lesion. A bullous component is occasionally visible.

As the angiosarcoma grows and spreads, the overlying atrophic epidermis may ulcerate, resulting in repeated episodes of bleeding and infection. Advanced cutaneous tumors may exhibit necrosis.

Angiosarcoma is found to occur in 0.07% to 0.45% of people who survive at least 5 years after a radical mastectomy. Although the majority of Stewart-Treves syndrome-related angiosarcomas are caused by post-mastectomy lymphedema, angiosarcoma development has been linked to persistent lymphedema of any origin. The precise mechanism underlying persistent lymphedema and angiosarcoma remains unknown. Stewart and Treves proposed that a systemic carcinogenic component was to blame for this process. It has also been proposed that lymphedematous areas undergo neoplastic change with the establishment of collateral circulation. Other hypotheses include a malignant transformation caused by lymphatic drainage blockage and decreased antigen presentation, resulting in cancer evading immune monitoring at an "immunologically privileged site."