A 68-year-old Asian woman presented with 2-week history of a painful left periareolar lump. Some of her medical history included: type II diabetes mellitus, chronic renal failure, moderate obesity, left chronic mastitis, mild hypercalcemia (2.60 mmol ⁄ L), and hypomagnesemia. Imaging and core biopsy of the breast diagnosed fat necrosis. The painful lump progressed into an ulcer over 4-month period. The second core biopsy of the breast lesion showed inflammatory changes only. Culture for Acid Fast Bacilli was negative while microscopy showed coliforms. The ulcer did not heal after several courses of antibiotics and wound dressing. Instead, it recurred and persisted for 7 months, progressing into necrosis. She underwent a vertical, central segmental wedge wide local excision with primary closure and satisfactory postoperative healing. The histology revealed extensive areas of ischemia, which were associated with abnormal small and medium size blood vessels (Fig. 1). The main abnormality of the blood vessel wall was calcification of the media (Fig. 2) with obliteration ⁄ hypertrophy of the intima and narrowing of the vessel lumen (Fig. 3). One of the vessels was completely occluded by thrombus (Fig. 4).In view of these findings, diagnosis of calciphylaxis in the breast was made, and previous biopsies were reviewed. These biopsies contained no blood vessels and suspicion of calciphylaxis could not have been raised earlier.Calciphylaxis occurring in the breast and resulting in chronic ulceration is uncommon. Only few cases have been reported in literature to date. It is characterized by calcification of small and medium sized vessels and is usually seen in patients with end stage chronic renal failure and secondary hyperparathyroidism. Our patient had normal parathyroid hormone level at time of presentation. Some cases have been reported in association with metastatic disease. The pathogenesis of calciphylaxis is not well understood