Toluidine Blue Stain as a Rapid Onsite Tool for Preliminary Diagnosis in Imprint Smears of Bronchoscopic Biopsy: A Cytohistopathological Correlation.

Lung cancer is currently the most common cause of cancer-related mortality, with 11.4% of cancers and 18% of cancer-related deaths worldwide whereas Indian figures are 6.9 and 9.3%, respectively. Hence, the need for early diagnosis. Bronchial biopsy has the highest sensitivity among all the samples that can be obtained by bronchoscopic techniques in case of endobronchial lesions. Imprint cytology has emerged as an important cytological method. Toluidine blue has been studied for its use as rapid onsite stain for cytological evaluation on various samples of cytology in different anatomic sites. This has helped in quick and less expensive, preliminary reporting.  This article aims to assess the efficacy of onsite toluidine blue stain on imprint smears of bronchoscopic biopsies to diagnose malignancy in suspected cases of lung carcinoma.  Prospective study on accuracy of a diagnostic test.  A total of 100 cases of bronchoscopy were included in the study. The patients were clinico-radiologically suspected to have brochogenic carcinoma and all of them were subjected to biopsy. Imprint smears were prepared from the bronchoscopy biopsy specimens. Smears were stained onsite with toluidine blue stain, and histopathology sections were stained with hematoxylin and eosin, also confirmed by immunohistochemistry.  Sensitivity and specificity of onsite toluidine blue stain for malignancy reporting were 97.9 and 80%, respectively, when compared to histopathology as standard.  Toluidine blue can be used as an onsite staining method on imprint smears of bronchoscopic biopsy for preliminary detection of lung malignancy.