Infection with the human immunodeficiency virus (HIV) is the main risk factor for developing cryptococcal meningitis. However, there is a poorly known entity, idiopathic CD4+ T-cell lymphopenia, which leads to an unexplainable CD4+ circulating T-cell deficit, predisposing patients to many complications, including infections caused by opportunistic microorganisms. We present the case of a patient with cryptococcal meningitis secondary to idiopathic T-CD4+ lymphopenia, which, as far as we know, is the very first case of its kind reported in Peru. This entity should be considered in patients negative for HIV infection developing non-common infections of the central nervous system, since outcome, management, and prognosis may be different in patients with this condition.

Infection with the human immunodeficiency virus (HIV) is the main risk factor for developing cryptococcal meningitis. However, there is a poorly known entity, idiopathic CD4+ T-cell lymphopenia, which leads to an unexplainable CD4+ circulating T-cell deficit, predisposing patients to many complications, including infections caused by opportunistic microorganisms. We present the case of a patient with cryptococcal meningitis secondary to idiopathic T-CD4+ lymphopenia, which, as far as we know, is the very first case of its kind reported in Peru. This entity should be considered in patients negative for HIV infection developing non-common infections of the central nervous system, since outcome, management, and prognosis may be different in patients with this condition.