Role of Whole Body PET/CT in Establishing the Diagnosis of Neurosarcoidosis: Case Report

Sarcoidosis is a multisystemic granulomatous disease of unknown etiology. Neurological symptoms occur in 5-15% of patients with sarcoidosis and are related to a whole spectrum of possible pathologies, including pachymeningitis, leptomeningitis, parenchymal involvement with mass lesions and/or white matter disease, myelitis, cranial neuropathies, peripheral neuropathy, and myopathy. Diagnosis can be challenging in patients without apparent intrathoracic involvement. We present a case of a patient with chronic leptomeningitis and resulting nonobstructive hydrocephalus in whom the presence of granulomatous inflammation was proven by the biopsy of fluorine-18-fluorodeoxyglucose (18F-FDG)-avid mediastinal lymph nodes detected on positron emission tomography/computed tomography (PET/CT). Prior computed tomography (CT) of the chest showed that they were normal in size. The patient was treated with glucocorticoids and infliximab, which resulted in clinical and radiographic improvement of the disease. This case argues for the important role of FDG-PET/CT in establishing the diagnosis of sarcoidosis.