Case Presentation: A 70-year-old man was admitted to our hospital due to prolonged fever and progressive polyarthritis. He had progressive supranuclear palsy and needed a cane when walking. Six-months before admission for his current illness, he had high fever and arthralgia in the right elbow, which was treated with loxoprofen. However, loxoprofen produced only temporary symptom improvement and, as time went on, arthritis developed in other joints as well. His activity levels gradually declined, with progressive debilitation. He was almost completely bedridden at the time of admission. Physical examination revealed swelling and tenderness of the right elbow and tenderness of the left elbow and bilateral shoulder, wrist and ankle joints. Axillary lymph nodes were palpable bilaterally, but hilar lymphadenopathy was not detected on chest radiography. Computed tomography disclosed bilateral pleural effusion and systemic lymphadenopathy including of axillary nodes. He had increased levels of C-reactive protein and soluble interleukin-2 receptor, and absence of rheumatoid factor and anti-citrullinated protein antibodies. Fluorine-18 fluorodeoxyglucose-positron emission tomography detected positive accumulation in axillary, iliac artery, inguinal and mediastinal lymph nodes, as well as bilateral elbow, shoulder, wrist, and ankle joints. Since we suspected a diagnosis of malignant lymphoma, we performed right axillary lymph node biopsy, which demonstrated epithelioid cell granulomas in the specimens. Angiotensin-converting enzyme levels were elevated (35.4 U/mL). We finally diagnosed that his arthritis was associated with sarcoidosis and treated the patient with prednisolone (0.5 mg/kg/day). Thereafter, fever and arthralgia disappeared and his activities of daily life improved from being bedridden to walking with a cane.

Discussion: Acute sarcoid arthritis is often associated with erythema nodosum and bilateral hilar lymphadenopathy, and it demonstrates favorable prognosis as resolved within 6 weeks in the majority of patients. Our patient lacked the typical features of the disease, so that diagnosis of sarcoid arthritis was delayed. Our case indicates that acute arthritis with progressive course may occur in sarcoidosis, in addition to prolonged fever and malaise.

Conclusions: Physicians should be aware of this type of acute progressive sarcoid arthritis with fever even if hilar lymphadenopathy or erythema nodosum is absent.

IMAGE 1: Fluorine-18 fluorodeoxyglucose-positron emission tomography findings