Varicella zoster virus rhombencephalomyelitis following radiation therapy for oropharyngeal carcinoma.

We report a 64-year-old man with a history of stage IV oropharyngeal squamous cell carcinoma treated with cisplatin and cetuximab followed by radiation therapy who developed a rapidly advancing rhombencephalomyelitis 11 months after the completion of radiation to the base of his tongue. His initial symptoms were left ear paresthesias, dysphagia, and progressive descending weakness. Routine cerebrospinal fluid (CSF) analysis was unremarkable. Initial MRI of the brain and cervical spinal cord revealed a demarcated symmetrical heterogeneously enhancing intramedullary lesion involving the cervicomedullary spinal cord. Progressive neurological worsening included increasing weakness of his limbs, facial weakness and ocular motility disorders and MRI revealed that the lesion was advancing into his pons and cervical spinal cord. Empiric treatment for radiation myelitis was initiated. Although CSF polymerase chain reaction was negative for varicella zoster virus (VZV), antibody studies revealed intrathecal synthesis of antibody to VZV and treatment for VZV was started as well. Improvement was slow and incomplete with subsequent worsening resulting in death in 5.5 weeks. The diagnosis of rhombencephalitis and myelitis following radiation therapy may be exquisitely challenging. The possibility of VZV, a treatable disorder, should be included in the differential diagnosis.