Dramatic change in disease activity visualized by PET in a patient with sarcoidosis

A 39-year-old female presented with malaise, weight loss, and generalized joint pain. Symptoms started 6 months prior to presentation and progressed over time. Laboratory tests revealed increased C-reactive protein (43.4 mg/L) and lactate dehydrogenase (330 U/L). Chest imaging showed mediastinal lymphadenopathy and nodular infiltration in the parenchyma of both lungs. Due to the subtle loss of weight and results of other imaging studies, positron emission tomography (PET) with fluorodeoxyglucose (FDG) was performed. Pathological FDG uptakes were observed in the cervical, hilar, and intraabdominal lymph nodes, lung parenchyma, liver, humerus, and ilium (Figure 1A). The patient was diagnosed as sarcoidosis according to the histopathological examination of a mediastinal lymph node. Corticosteroid and azathioprine were prescribed. Four months after treatment, a control PET scan was performed (Figure 1B). There was dramatic improvement in all anatomical sites compared with the first scan, correlating with symptom relief. In conclusion, PET scan may be a useful tool for monitoring disease activity in widespread sarcoidosis.