Exfoliative cytology in laryngology: comparison of cytologic and histologic diagnoses in 350 microlaryngoscopic examinations--a prospective study.

In a prospective study comprising 350 microlaryngoscopic examinations, the reliability of exfoliative cytologic diagnosis was evaluated in comparison with the histologic findings. In 157 of 190 lesions with histologically moderate and severe dysplasia, carcinoma in situ, and invasive carcinoma, the cytologic smears were positive. The sensitivity of the exfoliative cytologic method in the detection of "malignant" lesions was thus 83%. False-negative smears were more common after radiotherapy and in the group with moderate dysplasia. In 134 of 160 histologically benign lesions, the cytologic evaluation was negative. The specificity of the smear test was thus 84%. In at least one case the cytologic examination disclosed true malignancy that had been overlooked at biopsy.