Skin plaques in a woman with renal disease.

Volume 82, Number 10 www.aafp.org/afp American Family Physician 1257 A 44-year-old woman was admitted to the hospital for severe pain localized to her lower extremities. She had a history of diabetes mellitus and end-stage renal disease requiring hemodialysis. On the sixth day of hospitalization, she developed tender, flat, hyperpigmented, violaceous plaques with irregular borders on her buttocks and thighs (Figure 1). Laboratory results included the following: ionized calcium level of 4.28 mg per dL (1.07 mmol per L), phosphorus level of 5.9 mg per dL (1.91 mmol per L), parathyroid hormone level of 483 pg per mL (483 ng per L), protein C activity of 41 percent, and protein S activity of 325 percent. The plaques increased in size, followed by blistering and sloughing of the skin (Figure 2). Skin biopsy showed focal necrosis of the deep dermis, microthrombi, and calcification of the vessel walls.