[Neurosarcoidosis presenting with severe hyposmia and polyradiculopathy]

A 50-year-old woman presented with constriction sensation in the lower part of the chest, paresthesia in the right forearm and hypesthesia in the right thigh. One month later, she noticed a loss of sense of smell. The normal findings of the nasal mucosa and the impaired results of standard olfactory acuity test (T&T olfactometry) and intravenous olfactory test (Alinamin test) suggested a lesion proximal to the nasal mucosa. Sensory disturbances in the segmental areas of cervical, thoracic and lumbar regions were clinically and electrophysiologically attributed to polyradiculopathy. MRI of the brain and whole spine revealed no abnormalities. Cerebrospinal fluid examination showed lymphocytic pleocytosis. Sarcoidosis was diagnosed based on the findings including an elevated serum angiotensin-converting enzyme level, bilateral hilar lymphadenopathy on the chest CT and histological evidence of noncaseating granulomas. Methylprednisolone pulse therapy improved the olfactory and sensory disturbances. Neurosarcoidosis should be considered in the differential diagnosis of olfactory impairment.