Toluidine blue. An aid in the microlaryngoscopic diagnosis of glottic lesions?

The value of toluidine blue staining in vivo in the diagnosis of glottic lesions was examined by comparing the results obtained in a series with the histological findings. This material included 272 biopsy specimens from the vocal cords (202 microlaryngoscopic examinations). In 148 of these, the changes were classified as "malignant" (moderate and severe dysplasia and carcinoma) and in 124 as "benign." The sensitivity of the staining test in detection of malignant lesions was 91%. Among 13 false-negative results (9% of the malignant group), there was keratosis in 11. The overall specificity of the staining tests was 52%. The false-positive lesions displayed "benign" pathological alterations, such as inflammation and ulceration. False-positive findings were more common after radiotherapy. A correct diagnosis of malignancy on the basis of positive staining was more frequent the greater the intensity of staining.