Clinicopathologic features of Stewart-Treves syndrome.

AIMS: To demonstrate clinicopathologic features of Stewart-Treves syndrome (STS) including clinical manifestations, morphology, immunophenotype (especially c-MYC amplification), differential diagnosis, pathogenesis, treatment and prognosis. METHODS AND RESULTS: 17 cases of STS were retrospectively archived, involving 6 cases of postmastectomy, 3 cases of postoperative cervical cancer and 8 cases of chronic lymphatic obstruction without history of malignancy. Seven of 9 cancer patients had undergone radiotherapy. All the patients presented with lymphedema as the first sign. The lesions appeared as multiple reddish blue macules or nodules with polypoid and coalesce. Microscopic examination revealed infiltrative proliferation of irregular vessels in dermis and subcutaneous tissue. The tumorous endothelial cells displayed pleomorphism in morphology. The heteromorphic tumor cells expressed CD34, CD31, ERG, D2-40, c-MYC and factor VIII. Despite various treatment modalities, all cases died in an average of 13.6 months, with 1 case of loss to follow-up. CONCLUSIONS: STS is an extremely rare malignancy that arises from congenital or secondary chronic lymphedema. STS uniquely overexpressed c-MYC. In spite of poor prognosis, early detection is important to facilitate a full range of available therapies, even an opportunity for curative treatment. A low threshold for biopsy and early referral to an experienced multidisciplinary team are highly recommended for optimum management.