Chronic granulomatosis with persistent HSV intrathecal synthesis over three years: a rare complication of HSV encephalitis in adult.

A 62-year-old man developed HSV-1 encephalitis with involvement of the left fronto-temporal lobes and caudate nucleus, improving under acyclovir. One month later, he developed mild word-finding difficulty. MRI showed the emergence of ring-enhancing nodular lesions with surrounding edema, confined to previously affected areas. Extensive repeat investigations revealed no alternative diagnosis. The patient recovered and remained clinically stable during follow-up. MRI over three years showed slow regression of the nodular lesions. A lumbar puncture at 3.5 years confirmed ongoing intrathecal immunoglobulin synthesis, with HSV-1-specific intrathecal synthesis. This case illustrates a rare post-herpetic granulomatous evolution, previously reported in only a few adults.