Neurosarcoidosis pathologically diagnosed via biopsy of a normal-sized inguinal lymph node with fluorodeoxyglucose accumulation on positron emission tomography/computed tomography in a patient with a history of brain Ewing's sarcoma.

Neurosarcoidosis is a rare disease and is often difficult to diagnose. Herein, we report a case of neurosarcoidosis in a patient with a history of Ewing's sarcoma of the brain. He presented with fever of unknown origin, and a pathological diagnosis was obtained via biopsy of a normal-sized inguinal lymph node with fluorodeoxyglucose (FDG) accumulation on positron emission tomography/computed tomography (PET/CT). The condition could not have been diagnosed without FDG-PET/CT.