Cytologic diagnosis of primary pulmonary actinomycosis: report of two cases.

Two cases of primary pulmonary actinomycosis had a radiologic and clinical picture of malignancy. The cases were diagnosed by microscopic examination of sputum that had been embedded in paraffin. The sputum samples were sent to the cytology laboratory for screening for neoplastic cells, and colonies of Actinomyces were seen in all samples. The authors emphasize the difficulties that can be encountered by the cytopathologist in identifying classic actinomycotic colonies in debris.