The Complex Diagnostic Challenge in Children With Non–Central Nervous System Cancer and Cerebellar Mutism

Multiple etiologies should be considered in the differential diagnosis of immunocompromised patients with non–central nervous system cancer and viral infections who develop mutism. Acute cerebellitis, caused by infections or by neurotoxicity resulting from chemotherapy; paraneoplastic cerebellar degeneration; atypical posterior reversible encephalopathy syndrome; and acute disseminated encephalomyelitis may all cause mutism in such patients. This condition warrants prompt recognition and may require treatment with immunotherapy, as it may be an immune-mediated process. We present 2 patients with leukemia and viral illness who developed cerebellar mutism in the setting of acute cerebellitis and responded to immunotherapy, suggesting that the condition involved a parainfectious immune-mediated response.