Pulmonary cryptococcosis: Radiologic-pathologic correlates of its three forms

To better understand the radiographic appearance of pulmonary cryptococcosis, 23 human cases and three cases in zoo animals were studied in which both radiographic and pathologic material was available for correlation. Radiographs in 44 additional cases were studies in which documentation was microbiologic but not pathologic. Three forms of pulmonary cryptococcal disease are recognized: (1) air-space collections of fungus with minimal or no inflammatory reaction, causing well defined masses both radiographically and pathologically, as documented by five cases in this series; (2) granulomatous infection, demonstrated here by 21 cases, producing segmental consolidation, poorly defined masses, or 'infiltrative masses', often accompanied by lymph node enlargement; and (3) airway colonization without parenchymal infiltration resulting in no significant or specific radiographic findings and no specific pathology. The most specific and distinctive radiographic finding in pulmonary cryptococcosis is the 'infiltrative mass', which resembles a mass in one view and an infiltrate in the 90° different view. A review of cryptococcosis shows the value of pathologic correlation of the form of the disease in understanding the radiographic abnormalities.