Sarcoidosis Induced by Metal Particles From a Left Elbow Prosthesis

A 74-year-old woman with rheumatoid arthritis had developed severe pain in her left elbow 7 years previously and undergone joint replacement. Recently, the joint replacement surgery had to be repeated, and 3 months later, she was hospitalized because of rapid deterioration of kidney function, blurred vision, and eye pain. Levels of serum albumin-adjusted calcium (10.6 mg/dL), serum 1,25-dihydroxyvitamin D₃ (115 pg/mL), and lysozyme (27.5 μg/mL) were elevated, and kidney function was impaired (serum creatinine, 2.48 mg/dL). Biopsies of periarticular tissue and a left axillary lymph node revealed CD68-positive, non-caseating granulomatous tissue with multinucleated giant cells containing metal particles. In addition, kidney biopsy showed granulomatous tubulointerstitial nephritis with positive CD68 and 1α-hydroxylase staining. Sarcoidosis was diagnosed. We assumed that macrophages had phagocytosed metal particles generated by wear of the joint prosthesis, leading to formation of granulomas, which spread to the left axillary lymph nodes and then to the lung field and kidneys, where they caused acute granulomatous tubulointerstitial nephritis. Eventually, the granuloma cells acquired 1α-hydroxylase activity, resulting in 1,25-dihydroxyvitamin D₃ production and hypercalcemia, which caused acute kidney injury.