A 75-year-old female, with a past medical history of hypertension, developed progressive cerebellar ataxia a week after a respiratory viral infection. She reported dysarthria and gait unsteadiness. Her symptoms worsened for about 2 weeks and then remained stable. She was admitted to our service 1 year after symptoms onset, and she had been previously diagnosed with parainfectious cerebellar ataxia. She also reported a 6-month history of daily nausea and vomiting, weight loss of 66 pounds, and distal four limbs paresthesias.
Neurological examination revealed severe dysarthria, bilateral horizontal nystagmus, pronounced ataxia, and bilateral dysdiadochokinesia. Although she was unable to stand or walk unattended, there was no muscle weakness. She had generalized hypotonia. Deep tendon reflexes were normal in the upper limbs, and absent in the lower limbs. There was distal pinprick hypoesthesia in both upper and lower limbs, with reduced proprioception and vibration sense in the lower limbs. Cognition was preserved and there were no mood complaints. The patient denied bowel and bladder dysfunction. Blood exams were unremarkable. Electromyography revealed four limbs severe axonal sensitive polyneuropathy, with mild motor involvement. She was prescribed high-dose intravenous methylprednisolone 1 g qd for 3 days based on the hypothesis of an auto-immune condition, but there was no clinical improvement. Serological screening was requested and included protein electrophoresis, anti-tissue transglutaminase IgG and IgA, anti-gliadin IgA, IgG, IgM, and anti-GAD and the results were non-reactive. Paraneoplastic antibodies panel, which was also negative, comprised anti-HU, anti-YO, anti-RI, anti-amphiphysin, anti-CV2, anti-MA2, anti-MGT30, AGNA and anti-recoverin. Lumbar puncture was performed 1 year after symptoms onset, and spinal fluid analysis showed 4 cells, protein of 28 mg/dL and glucose of 70 mg/dL. Brain MRI (Fig. 1a) displayed cerebellar atrophy whereas the cerebral cortex had no abnormalities. Further tests were requested to evaluate the frequent vomiting, which persisted during the entire period of hospital stay. Abdominal MRI (Fig. 1b) showed a right exophytic heterogeneous renal mass. Radiology determined that it was category III in the Bosniak Classification for complex renal cysts, suggesting a high risk of malignancy [4]. The tumor was subsequently resected, and the histopathologic analysis revealed a clear cell renal carcinoma (Fig. 1c and d). The lesion had a cystic greater than nodular component, which is atypical. Predominantly cystic lesions suggest fast-growing tumors [5].
On 6-month follow up after tumor extraction, there was complete resolution of gastrointestinal symptoms, and partial dysarthria improvement. Ataxia, however, remained stable. The patient was referred to the Movement Disorders Outpatient Clinic. There were no further therapeutic interventions after hospital discharge.