Cryptococcus neoformans is an encapsulated yeast acquired through inhalation of spores from contaminated soil (particularly pigeon droppings). The polysaccharide capsule is the primary virulence factor, inhibiting phagocytosis and suppressing T-cell responses. In immunocompetent hosts, cell-mediated immunity typically contains the infection as granulomas. In immunocompromised patients (especially those with CD4 counts < 200 cells/mcL), the organism proliferates unchecked in alveolar macrophages, causing pneumonia with a propensity for hematogenous dissemination to the central nervous system (cryptococcal meningitis).