An Unusual Case of Sarcoidosis with a Prolonged Fever and Progressive Arthropathy.

A 70-year-old man had developed a high fever and arthralgia in his right elbow 6 months prior. Loxoprofen improved the symptoms temporarily, but arthropathy developed in other joints. Long-term recurrent arthropathy and the fever caused activity reduction and progressive debilitation. We performed fluorine-18 fluorodeoxyglucose-positron emission tomography and detected a positive accumulation in multiple joints and lymph nodes. A lymph node biopsy revealed epithelioid cell granulomas, which, along with elevated angiotensin-converting enzyme levels, led to the diagnosis of sarcoid arthropathy. After prednisolone administration, the fever and arthralgia resolved, and his activities of daily living improved. Clinicians should be aware of this type of sarcoid arthropathy.