Abstract
Neuromyelitis optica spectrum disorder (NMOSD) is a relapsing inflammatory disorder of the central nervous system most commonly associated with aquaporin-4 antibody (AQP4) and anti myelin oligodendrocyte antibody (MOG). Most commonly an idiopathic autoimmune condition, paraneoplastic NMOSD is a rare but important differential in older individuals presenting with LETM and should prompt investigation for a malignancy. We describe a case of NMOSD presenting as longitudinally extensive spinal cord lesion in a previously healthy 74 year old Asian female with renal cell carcinoma. Originally thought to be a metastatic intramedullary renal cell carcinoma metastasis, imaging was more consistent with a longitudinally extensive transverse myelitis (LETM) lesion. AQP4 and MOG antibodies were negative in serum and cerebrospinal fluid. There was imaging improvement with limited functional recovery following initial treatment with intravenous methyl prednisone, plasma exchange, intravenous immunoglobulin, and rituximab. This case also highlights the need to identify candidate biomarkers associated with seronegative neuromyelitis optica spectrum disorder to improve early diagnosis and early management.
