Derman necrosis due to thrombosis in severe secondary hyperparathyroidism.

Two patients had gangrenous dermal necrosis associated with chronic renal disease and secondary hyperparathyroidism. Thromobosed and heavily calcified small arteries were underlying the infarcted areas. One patient had severe hypotension secondary to hemorrhage, which immediately preceded the appearance of dermal lesions. Both patients had notably elevated serum parathyroid hormone and serum alkaline phosphatase levels, as well as severe hyperphosphatemia. Therapy with phosphate binders and calcium and vitamin D supplementation corrected the hyperphosphatemia and reduced serum alkaline phosphatase levels. One patient died; the other patient's dermal lesions healed completely. Localized thrombosis, rather than obliterative intimal proliferation, represents a unique cause of dermal necrosis in this condition.