Mites in pulmonary cytology specimens

Mites were observed in 55 pulmonary specimens examined routinely over a 4.5-yr period. The 55 specimens included 33 spontaneous and 12 aerosol-induced sputum samples, nine bronchial washings, and one fine-needle aspirate. Two specimens contained only fragments of mites; however, in most cases the mites were relatively intact. Many were identified as Tyrophagus sp, but a few were definitely not Tyrophagus sp. Although only a single mite was noted in most instances, eight specimens contained more than one, with the maximum being six. No patient was found to have a mite in more than one specimen. Mite eggs were found in five of the specimens containing mites. One specimen contained adults and a larval form. Mites appeared to be surrounded by acute inflammatory cells in 13 cases. Specimens were processed by the Saccomanno blending technique with smears prepared by pipetting a portion directly onto a slide or by utilizing a cytocentrifuge. No mites were found in nonpulmonary specimens. Both a seasonal variation and an interobserver variability were found. Mites often resemble specimen contaminants, such as food, and may be overlooked on routine screening. Mites are known to represent or produce a respiratory allergen, but the significance of their presence in pulmonary cytology specimens has not been determined.