Strongyloides stercoralis in routine Papanicolaou-stained sputum smears.

Three cases are reported in which the initial detection of unsuspected Strongyloides stercoralis infestation was made on Papanicolaou-stained smears of sputum submitted for routine cytopathology. All cases were subsequently confirmed by the examination of stool specimens. A common factor in the three cases was long-term treatment with corticosteroids for chronic respiratory disease. All three patients responded to treatment with antihelminthics. The significance of this parasite is discussed, and its appearance in Papanicolaou-stained smears is described and illustrated.