Multivesiculated macrophages: their implication in fine-needle aspiration cytology of lung mass lesions.

Alveolar macrophages are almost invariably present in percutaneous fine-needle aspiration cytology of the lung. They may predominate, appear foamy and finely vesiculated, or may reflect the cellular composition of the lung mass lesion. In a review of 172 cases of "negative for malignant cells" from the percutaneous lung fine-needle aspiration cytology file in an 8-year period at Hines VA Hospital, the vacuolated macrophages were evaluated qualitatively and quantitatively. Among the 53 cases (34%) showing vacuolated macrophages, only 5-25% of the cells were multivesiculated, the cytoplasmic vacuoles were few, focal, and occasionally global, and the majority of the vacuolated macrophages contained anthracotic or hemosiderin pigments. One case exhibited striking multivesiculation in at least 95% of macrophages and also in bronchial and alveolar cells, fibroblasts, and endothelial and inflammatory cells, a finding consistent with amiodarone toxicity (index case 1). The diagnosis was confirmed on subsequent transbronchial lung biopsy. In another patient with clinical HIV infection, the multivesiculation was also seen in 95% of the macrophages with associated acute inflammatory exudate, coccobacilli, and a positive culture for Rhodococcus equi (index case 2). In most cases, the vacuolated macrophages are reactive and inflammatory. Occasionally, as in our index cases they may actually indicate a specific diagnosis.