Chronic meningitis with marked unilateral tentorial pachymeningitis.

Two cases of chronic meningitis with marked granulomatous thickening of the cerebellar tentorium are presented. The clinical features of both cases were those of chronic meningitis, namely, incessant chronic headache, long-lasting moderate increase of intracranial pressure, multiple cranial nerve involvement, slight lymphocytosis, and increased protein in cerebrospinal fluid. The characteristic finding on computed tomography scan was slight, high density of the unilateral cerebellar tentorium with marked contrast enhancement. Both patients died of complications, and necropsy revealed marked granulomatous thickening of the unilateral cerebellar tentorium. Although noninfectious disease was strongly suspected, the etiology could not be specified either clinically or by necropsy.