Invasive cavitary pulmonary aspergillosis in patients with cancer: a clinicopathologic study.

We studied the histopathology and clinicopathologic correlates of invasive cavitary pulmonary aspergillosis in 11 immunosuppressed patients with disseminated malignancy. In most patients cavities were produced by separation of necrotic from viable lung, resulting in an intracavitary sequestrum ("lung ball"). Central dissolution of large necrotic areas and suppurative granulomatous aspergillary pneumonia were additional causes of cavities in three patients. In four patients with chronic cavities sequestra had been replaced by intracavitary mycetomas ("fungus balls"). Neutrophils usually were numerous at the interface of the sequestrum and adjacent lung, but were minimally present in three patients with prolonged severe neutropenia. The lack of neutrophils in some patients suggests that factors other than neutrophil-derived proteases may be important in cavity formation. A prominent giant cell reaction was seen in three patients with chronic cavities. Hemoptysis occurred in five patients and massive hemoptysis due to a bronchoarterial fistula caused the death of one patient. The "air-crescent" sign was not observed radiographically in any patient and is therefore considered to be an insensitive marker for lung cavitation in invasive aspergillosis. Persistent intracavitary fungal growth may serve as a reservoir for recurrent fungal invasion in patients with prolonged or repeated episodes of severe neutropenia.