The role of smear cytology in laryngeal diagnosis.

There may be great difficulty especially in diffuse lesions, in obtaining representative laryngeal biopsy specimens. Therefore the reliability of laryngeal smear cytology was evaluated in comparison with the histologic diagnosis. The cytologic specimens were taken during 520 microlaryngoscopic examinations (direct technique). The sensitivity of the direct cytologic method in the detection of moderate dysplasia, severe dysplasia-carcinoma in situ, and invasive carcinoma was 45% (17/38), 83% (59/71), and 93% (137/147), respectively. A false negative cytologic reading was more frequent after radiotherapy. The specificity of the direct cytologic technique in the detection of histologically "benign" lesions was 80% (210/264). In 23 patients cytologic smears were obtained at mirror laryngoscopy (indirect technique). Both the direct and indirect cytologic tests are easy to perform, quick, and may be of diagnostic value in laryngeal diagnosis, especially in screening examinations. However, cytology cannot supersede the histological examination of biopsy specimens.