Calciphylaxis Mimicry in End-Stage Renal Disease: Acute Limb Ischemia From Calcific Peripheral Arterial Disease

Calciphylaxis is a life-threatening complication of end-stage renal disease (ESRD) characterized by painful necrotic skin lesions resulting from small-vessel (arteriolar) calcification, thrombosis, and subsequent ischemic tissue necrosis. However, not all ischemic lesions in dialysis patients represent calciphylaxis. We present a 44-year-old man with ESRD on hemodialysis who developed progressive bilateral digital necrosis initially suggestive of calciphylaxis, given severe hyperphosphatemia and secondary hyperparathyroidism. Lesion morphology demonstrated well-demarcated distal gangrene without retiform purpura or induration, features atypical for calciphylaxis. Multimodal evaluation revealed an alternative diagnosis. Radiographs demonstrated extensive medial arterial calcification, while noninvasive vascular testing showed markedly reduced ankle-brachial indices and abnormal pulse volume recordings. Duplex ultrasonography identified hemodynamically significant arterial disease, and magnetic resonance imaging confirmed soft-tissue nonviability without osteomyelitis. Collectively, these findings supported acute limb ischemia secondary to advanced calcific peripheral arterial disease rather than calciphylaxis. The patient was managed with a vascular-focused approach, including evaluation for revascularization and surgical planning. This case highlights a critical diagnostic pitfall in ESRD, where dialysis-associated vascular calcification may mimic calciphylaxis while representing macrovascular occlusive disease. Accurate differentiation through careful clinical assessment and multimodal vascular evaluation is essential, as management strategies and outcomes differ substantially.