RESUMO
INTRODUCTION: Paraneoplastic motor neuron disease are rare among patients with renal cell carcinoma. OBJECTIVE: Present the clinical and electrophysiological evolution of a patient with a motor neuron disease and hypernephrome. CASE REPORT: A 60 years old woman, affected only by high level pressure since 10 years ago. She noticed sudden palsy of the left leg and 10 months later an abdominal ultrasound showed a renal cell carcinoma, discovered without other symptoms than neurologic. After radical nephrectnomy, the patient was treated with recombinant interferon alpha 2b. The neurologic damage advanced and she has a flaccid weakness and muscle atrophy in the legs and brisk reflexes, also in wasted limbs. There is Babinski, fasciculations, light flaccid dysarthria and laryngospasm. Peripheral nerve conduction studies are within normal limits. The electromyogram show positive sharp waves in both legs and left hand. Recruitment patterns are decreased and there are fasciculations in the tongue, upper and lower limbs. The magnetic resonance of the brain and spinal cord is normal. There are not evidence of metastasis. The question of whether or not this is a paraneoplastic form of motor neuron disease remain unclear. CONCLUSION: This case suggest the need to consider a renal cell carcinoma in the course of a motor neuron disease.