Caseous Peripheral Medial Arterial Calcification With Inflammation and Luminal Occlusion.

BACKGROUND: Caseous calcification is a rare form of calcification characterized by liquefactive degeneration into amorphous, cheese-like material. Although well recognized in mitral annular calcification, it has not been reported in peripheral arteries. CASE SUMMARY: A 51-year-old man with end-stage renal disease on peritoneal dialysis developed chronic limb-threatening ischemia requiring below-the-knee amputation despite revascularization. Radiography, micro-computed tomography, and histology of the anterior tibial artery demonstrated focal caseous calcification within extensive medial calcification. Unlike sheet-like calcification with minimal inflammation, caseous lesions were associated with numerous multinucleated giant cells, macrophages, and T lymphocytes, as well as thrombus formation, severe luminal narrowing, and focal chronic total occlusion. DISCUSSION: This case provides the first histopathological evidence of peripheral arterial caseous calcification associated with severe inflammatory response and luminal occlusion. TAKE-HOME MESSAGE: Caseous calcification may represent a distinct inflammatory phenotype of medial arterial calcification that contributes to luminal narrowing and thrombosis in the absence of atherosclerosis.