Pulmonary cryptococcosis.

Cryptococcus neoformans is a ubiquitous soil fungus that rarely causes pneumonia in normal hosts but is a common cause of opportunistic infection. Pulmonary disease is initiated by inhalation of the organism, and a spectrum of radiographic manifestations can be seen. The most common finding is a poorly marginated nodule or mass. Lobar or segmental parenchymal opacities and, less commonly, a diffuse scattered nodular or reticulonodular pattern have also been observed. Associated adenopathy, pleural effusions, and cavitation are uncommon; when present, these are more common in immunocompromised patients. Establishing the diagnosis can be difficult, but pulmonary cryptococcosis should be considered in the differential diagnosis of patients in the proper clinical setting and with compatible radiographic findings.