FDG-PET abnormalities leading to the diagnosis of an unusual case of probable neurosarcoidosis

Sarcoidosis is a systemic illness of unknown etiology, characterized histologically by the formation of noncaseating granulomata in the affected tissue. The most common sites of involvement include the pulmonary system; however, neurologic involvement may be seen as well, though typically presenting with systemic findings.1 Diagnosing sarcoidosis is challenging due to the lack of reliable serum or imaging markers and hence typically relies on tissue diagnosis.1 Although fluorodeoxyglucose positron emission tomography (FDG-PET) has been used in the diagnosis of sarcoidosis, its role is not well established.2–4 FDG-PET is an imaging technique wherein FDG, a glucose analogue, is introduced into the body, where it is metabolized with varied rates by different cells.2–4 Certain conditions, such as malignancy or inflammatory disease, demonstrate increased metabolism and therefore uptake of FDG, which is visualized by PET scan. We report a case of probable neurosarcoidosis presenting with an unusual pattern of FDG uptake without concomitant brain MRI findings.