Cytology of allergic bronchopulmonary aspergillosis.

The cytologic features of a case of allergic bronchopulmonary aspergillosis (ABPA) are reported and the literature reviewed. The bronchial brushing smears in this case showed mucus that contained laminated aggregates of eosinophils with scattered Charcot-Leyden crystals and fungal hyphae. These cytologic findings, overlooked by the initial examining pathologist, reflected the "mucoid impaction of bronchi" component of ABPA and are therefore diagnostic of ABPA. A cytologic diagnosis of a clinically unsuspected ABPA would lead to the correct treatment and prevent unnecessary surgery.