Introduction Neurosarcoidosis is a rare disease with variable clinical and radiological manifestations. We report a case of longitudinally extensive transverse myelitis mimicking NMO that was pathologically confirmed to be sarcoidosis.

Case a 50 year old Caucasian man presented with left arm paraesthesia, sensory and gait disturbance. Spinal MRI showed a swollen longitudinally extensive cord lesion (6 spinal segments) with peripheral enhancement. Brain MRI was normal. The CSF protein was 0.51 g/L and oligoclonal bands were restricted to the CSF. AQP-4 and MOG antibodies were negative. Serum ACE, vasculitis, and infectious screens were negative. The patient was administered a four day course of 1 g of iv methylprednisolone once daily, and improved clinically and radiologically. However, subsequent deterioration prompted treatment with plasma exchange (6 courses) and rituximab, which was ineffective. The peripheral nature of the enhancement pattern and steroid responsiveness prompted a whole body PET, showing FDG avid mediastinal lymph nodes, and a biopsy demonstrated non-necrotizing granulomas. Mycobacteria were absent. The diagnosis of sarcoidosis was made and the patient was initiated on intravenous infliximab (500 mg at 0, 2, 6 and 8 weeks). The patients gait and sensation improved.

Conclusion Neurosarcoidosis should be included in the differential of longitudinally extensive transverse myelitis, particularly in AQP4-IgG seronegative patients.

References 1. Tavee JO, Stern BJ. Neurosarcoidosis. Continuum (Minneap Minn)2014Jun;20(3 Neurology of Systemic Disease):545–59.

2. Sohn M, Culver DA, Judson MA, Scott TF, Tavee J, Nozaki K. Spinal cord neurosarcoidosis. Am J Med Sci2014Mar;347(3):195–8.

3. Flanagan EP, Kaufmann TJ, Krecke KN, Aksamit AJ, Pittock SJ, Keegan BM, Giannini C, Weinshenker BG. Discriminating long myelitis of neuromyelitis optica from sarcoidosis. Ann Neurol2016Mar;79(3):437–47.