Localized cytomegalovirus encephalitis contiguous to metastatic nasopharyngeal carcinoma.

We report a case of focal infection of the brain with cytomegalovirus (CMV) in a 14-year-old boy with metastatic lymphoepithelioma (nasopharyngeal carcinoma). Cytomegalovirus-bearing subependymal glia were only seen in the fourth ventricle, in close proximity to tumor cells, these were associated with an intense inflammatory cell exudate. The latter was due to enterococcal meningitis. There was no evidence of systemic CMV infection, and the typical encephalitis with glial nodules seen in acquired forms of the disease was lacking. We postulate that the infection gained access to the brain either with the tumor cells, which happened to carry CMV genome, or with virus-carrying polymorphonuclear leukocytes migrating to the bacterial meningitis. It is also possible that the proliferating subependymal glia were unduly susceptible to CMV when the host defense mechanisms were compromised.