Papillary endothelial hyperplasia of the breast: the great impostor for angiosarcoma: a clinicopathologic review of 17 cases.

Seventeen cases of papillary endothelial hyperplasia (PEH, Masson's vegetant intravascular hemangioendothelioma) involving breast or mammary subcutaneous tissues are described. The mean patient age was 59; 14 (82%) were female and 12 (71%) presented with a mass. Nine women had mammographic evaluation, 3 of whom had microcalcifications. Five neoplasms were discovered by routine mammography. Sixteen cases were 2.7 cm or less in greatest dimension, and 8 (47%) were associated with a thrombus and/or cavernous hemangioma. Follow-up in 10 cases (up to nearly 8 years) showed no recurrences. Fifty-nine percent of the cases were received at AFIP for consultation with a working diagnosis of angiosarcoma. Features that help distinguish PEH from angiosarcoma include circumscription of the lesion, location in a vessel or association with thrombus, and papillary architecture without significant cytologic atypia or areas of solid growth. The recognition of the morphologic features of this lesion and its inclusion in the differential diagnosis of vascular mammary tumors will reduce the likelihood of its misdiagnosis as an angiosarcoma and avoid unnecessary and aggressive therapy.