A solitary intracranial rich focus with early meningeal involvement: A correlative image.

•Rich foci are caseating brain tuberculous (TB) granulomas surrounding the immigrated TB bacilli.•Rich foci are hypothesized as an underlying pathological mechanism of TB meningitis.•The hypothesis is based on necropsy studies and has rarely been depicted in vivo.•Ruptured foci discharge their contents into the neighboring subarachnoid space.•Discharged contents trigger a T cell response, leading to inflammatory meningitis.