Ever-changing concepts of calciphylaxis.

Calciphylaxis is clinically characterized as a serious condition with necrosis of the skin and adipose tissue, leading to a high mortality rate due to sepsis and ischemia (1). Although this abnormality is seen predominantly in patients with end-stage renal disease, it should be distinguished from simple metastatic calcification. Histologically, calciphylaxis is associated with medial calcification and intimal calcification of medial and small arteries with secondary gangrene of the tissue (2). Ever since the first clinical report in a uremic patient by Anderson in 1968 (3), the clinical features and concepts of calciphylaxis have been changing even recently. This sometimes leads to marked discrepancy in the discussion of cases with calciphylaxis. Furthermore, new entities have also been added to the list of pedisposing factors for calciphylaxis. Such changes are partly due to the changing patterns of bone disease type and also those of therapeutic modalities such as vitamin D and calcium salts. Calciphylaxis had been thought to involve almost exclusively distal sites in uremic patients with significant hyperparathyroidism and elevated Ca×P products (1). In such patients, surgical parathyroidectomy improves the signs and symptoms dramatically. By contrast, proximal lesions have been reported during the last decade (4). Obesity, female, hypoalbuminemia, diabetes and other factors have been suggested as new risk factors for the development of calciphylaxis (5). In such patients, parathyroidectomy may not be successful to control calciphylaxis as suggested by several reports. Although hyperbaric oxygen has been shown to reverse ulceration in some patients (6), it is much more important to recognize calciphylaxis at the early stage with non-ulcerating plaques as recently suggested by Fine and Zacharias (7). In this issue of Internal Medicine, Oikawa and associates report a case of penile calciphylaxis (8).