Vascular proliferations of the breast.

Vascular proliferations of the breast are uncommon but potentially diagnostically challenging lesions. Clinically apparent processes are more likely to be malignant; however, a range of benign entities which must be differentiated from angiosarcoma also exists. This review discusses first, breast lesions of apparent vascular origin, then benign and histologically bland perilobular, cavernous and capillary haemangiomas. Subsequently, more diagnostically challenging, atypical haemangiomas, papillary endothelial hyperplasia, angiomatosis and angiolymphoid hyperplasia with eosinophilia (epithelioid haemangioma) are considered. In addition, lesions with low-grade malignant potential such as haemangiopericytomas and epithelioid haemangioendotheliomas may rarely present in the breast. However, primary angiosarcomas and radiation-associated vascular lesions are reviewed in depth, as these entities are of greatest clinical and pathological significance.