# Cerebellar Ataxia With Neuropathy and Bilateral Vestibular Areflexia Syndrome Coexisting With JAK2-Positive Polycythemia Vera and Myelofibrosis

## TL;DR

A rare case of CANVAS coexisting with JAK2-positive polycythemia vera and myelofibrosis is reported, highlighting a possible but unexplained connection between these conditions.

## Contribution

This is the second reported case of CANVAS coexisting with polycythemia vera, offering a rare clinical observation for further study.

## Key findings

- The patient exhibited symptoms of CANVAS alongside JAK2-positive polycythemia vera and myelofibrosis.
- Thalidomide use for polycythemia vera was linked to the patient's neuropathy and eventual death.
- The coexistence of CANVAS and polycythemia vera remains poorly understood and warrants further investigation.

## Abstract

Cerebellar ataxia with neuropathy and bilateral vestibular areflexia syndrome (CANVAS) is a rare, progressive, neurodegenerative disorder characterized by late-onset ataxia, bilateral vestibular impairment, and sensory neuropathy.

A 51-year-old male presented to the hospital with worsening dizziness, tremulousness of limbs, and falls during the preceding year. The patient experienced gradually progressive sensorimotor lower motor neuron quadriparesis, asymmetric ataxia, chronic pancerebellar dysfunction, oscillopsia, and impaired vestibulo-ocular reflex. His comorbidities included poorly controlled type 2 diabetes mellitus, chronic alcohol use, and thalidomide therapy for polycythemia vera with myelofibrosis. Diagnostic workup revealed sensory axonal neuropathy, hypercellular bone marrow with myelofibrosis, and utriculo-saccular dysfunction. Diabetes and thalidomide- and alcohol-related complications were presumed to be the reason for the patient's symptoms, but investigations revealed a diagnosis of CANVAS coexisting with polycythemia vera. The patient was treated with rehabilitation exercises and medications that slightly improved but did not resolve his symptoms. More than 1 year after the patient's last follow-up, a physician at another hospital discontinued the thalidomide prescription because of the patient's neuropathy. Two months later, the patient developed febrile neutropenia and died of pneumonia and sepsis.

To our knowledge, CANVAS coexisting with polycythemia vera has only been reported once in the literature. The significance of this coexistence is not clear. Future case studies may help elucidate a link between these two entities.