Bell-shaped sensory impairments of all modalities in a neurosarcoidosis patient

Abstract

We describe a 45-year-old man with neurosarcoidosis complaining of bell-shaped tightening and pain with sensory disturbance of superficial and deep sensations. The patient showed subacute progressive sensory impairment in bilateral C7-Th12 dermatomes. Triceps and patellar tendon reflexes were decreased. Chest X-ray revealed bilateral hilar lymphadenopathy without pleural effusion. There was abnormal accumulation of gallium in the bilateral hilar lymph nodes, parotid glands, and lacrimal glands on scintigraphy. Examination of bronchoalveolar lavage fluid showed an elevated CD4/CD8 ratio. Transbronchial lung biopsy showed non-caseating granulomas with many epitheloid cells and occasional Langhans giant cells without any necrotic lesion. The tuberculin reaction was negative, and elevation of serum lysozyme and IgG level were seen. These findings fulfilled the clinical criteria for sarcoidosis. Spine MRI demonstrated no abnormality. Studies of short-latency somatosensory evoked potentials showed delayed N13 latency and absent N19 and N28 potentials bilaterally. A nerve conduction study revealed no abnormality. The patient's muscle strength was normal through the entire clinical course. Therefore, we consider that his sensory impairment was caused by peripheral neuropathy, especially in the dorsal root region. Neurosarcoidosis is important for differentiating bell-shaped sensory impairments of all modalities.