JC virus granule cell neuronopathy associated with Ruxolitinib: A case report and review of the literature

•We report here a case of JC virus granule cell neuronopathy associated with Ruxolitinib•It is worthwhile considering the possibility of JCV-GCN in myelofibrosis patients receiving ruxiolitinib, who present with progressive cerebellar symptoms and cerebellar atrophy.•Combination therapy using mefloquine and mirtazapine may be an effective treatment.