Varicella-zoster viral meningitis mimicking lymphoma

We report the case of a 30-year-old HIV-infected man admitted for a meningeal syndrome and a zoster rash. The CSF had cytological features suggesting a primary CNS lymphoma (PCNSL). The large lymphoid cells had a fine chromatin with nucleoli, a basophilic cytoplasm with azurophilic granules and high mitotic activity. Several arguments demonstrated the viral origin of the meningitis: the large lymphoid cells were of T origin with no evidence of clonal TCR γ gene rearrangement. The PCR was positive for Varicella-Zoster Virus (VZV) and EBV DNA. Clinical evolution was favorable under acyclovir. We should be cautious in the differential diagnosis between viral meningitis and PCNSL.