Résumé : A case of asynchronous bilateral breast necrosis in a 40-year-old woman with untreated chronic hypercholesteraemia is described. Mastectomies were performed, and histological examination revealed bilateral breast calciphylaxis characterized by extensive vascular calcification with coagulative necrosis. Breast calciphylaxis is a rare disease clinically characterized by progressive tissular necrosis with secondary cutaneous ulceration and by vascular calcification and thrombosis. However, the nature of the vascular calcification has remained poorly understood up to now, owing to the absence of any precise mineralogical examination. In this case the mineral deposits were analysed for the first time: only hydroxyapatite was found. The etiology is discussed, and the high cholesterol rate of the patient is implicated. © 2004 Elsevier Ltd. All rights reserved.