Cutaneous necrosis of the proximal lower extremities in a patient with end-stage renal disease is the classic presentation of calciphylaxis, an untreatable, rare, generally fatal necrotizing cutaneous syndrome. Type 1 primary hyperoxaluria (PH-1) usually presents in childhood with recurrent urolithiasis. Since enzymatic studies to confirm the metabolic defect are now available, some cases of idiopathic renal failure in adulthood have been shown to be caused by PH-1. These patients may develop vascular oxalate deposits resulting in livedo reticularis and distal acral vascular insufficiency.