longitudinally extensive myelitis as first presentation of renal cell carcinoma

Longitudinally extensive myelitis (LETM) is spinal cord inflammation involving three or more vertebral segments. The most common cause of LETM is neuromyelitis optica spectrum disorders (NMOSD) and other inflammatory demyelinative disease. Neuromelitis optica (NMO) is a demyelinating syndrome of the nervous system by attacks of optic neuritis and myelitis. Intramedullary tumors such as astrocytoma, ependymoma, and intravascular lymphoma are other causes of LETM, and intramedullary metastasis is very rare. However, development of progressive myelopathy in the absence of antecedent neurological symptoms and without signs indicating dissemination beyond the spinal cord is a diagnostic challenge, and rule out of other causes of myelitis should be done.1 There have been many reports of patients with demyelinating disorders mimicking spinal cord tumors,2-5 and on the contrary, we report a rare case of renal cell carcinoma (RCC) presenting by LETM without manifestation of primary tumor. A 70-year-old farmer without any other medical history was referred in October 2014 with right hand paresthesia and neck pain that radiated to shoulders. The first cervical magnetic resonance imaging (MRI) showed cervical spondylosis without abnormality in spinal cord parenchyma. The patient was treated for cervical spondylosis. Two months later he noticed atrophy of first interosseous muscle and brain MRI was performed, which revealed a few small vessel ischemia and electromyography study showed motor neuron disease. In May 2015, he was referred to our hospital with paraparesis (left more than right). At physical examination, mental examination was normal and paraparesis with a motor grade 3/5 in left and 4/5 in right side was detected without sphincteric problem. The patient underwent whole spine MRI, which revealed an extensive intramedullary hyperintensity in T2-weighted MRI involving predominantly central spinal cord and extended until medulla location (Figure 1, A). Routine investigations including hematology, Iranian Journal of Neurology