Isolated Muscular Sarcoidosis Revealed by Hypercalcemia and 18F-FDG PET/CT.

A 43-year-old woman, with previous history of renal lithiasis, was admitted on an emergency for severe hypercalcemia fortuitously discovered in a context of rapidly progressive kidney failure. An F-FDG PET/CT performed to rule out underlying malignancy revealed an intense diffuse and isolated muscular FDG uptake with fascia infiltration on the CT finding. A muscular biopsy was performed and demonstrated a non-necrosing granuloma with multinucleated giant cells consistent with muscular sarcoidosis. A corticotherapy was started with a rapid normalization of serum calcium level. The follow-up F-FDG PET/CT 4 months later showed a complete response of the sarcoidosis myositis.