Unusual case of calciphylaxis associated with metastatic breast carcinoma

Calciphylaxis is a relatively rare disorder associated with calcification of small- and medium-sized blood vessels, progressive ischemic skin necrosis, and ulcerations. It is usually seen in patients with end-stage renal disease with secondary hyperparathyroidism and is occasionally seen in primary hyperparathyroidism, hypercalcemia of malignancy, and end-stage liver disease. We report an unusual case of calciphylaxis seen in association with metastatic breast carcinoma in the absence of end-stage renal or parathyroid disease. A 73-year-old woman presented with painful leg ulcers. Serum calcium levels and parathormone levels were within normal limits. Skin biopsies from the ulcers revealed small- to medium-sized subcutaneous arteries with calcification of the media. Some of the arteries were narrowed by fibrointimal hyperplasia and fibrin thrombi. Calcification of the subcutaneous fat, fat necrosis, and suppuration were also seen. Calciphylaxis associated with metastatic osteolytic breast carcinoma is rare. Although end stage renal disease with secondary hyperparathyroidism is the most common cause of calciphylaxis, this case demonstrates that less common conditions with normal serum calcium and parathormone levels may also cause it.