Concordance of Bronchoalveolar Lavage Cytology with Transbronchial Lung Biopsies in Non-neoplastic Pulmonary Diseases

Abstract

Introduction: In many pulmonary diseases, despite radiological & clinical investigations, laboratory tests and function studies, the diagnosis becomes difficult. Bronchoalveolar Lavage (BAL) is a minimally invasive method in which cells are collected from bronchial and alveolar spaces for cytology. This is facilitated by using a flexible bronchoscope with which a biopsy is taken following BAL. Bronchoscopy with BAL when used appropriately can offer correct diagnosis which in turn aids in proper management of the patient. Aim: To find the concordance of BAL findings with the histopathological features of Transbronchial Lung Biopsy (TBLB) in non-neoplastic lung diseases. Materials and Methods: It was a retrospective study conducted in Kempegowda Institute of Medical Sciences, Bengaluru, Karnataka. A total of 40 patients presenting with clinico-radiological findings, suggesting a non-neoplastic lung disease in the year 2019, undergoing bronchoscopy with BAL and concurrent TBLB were chosen. The BAL fluid was processed and differential count of cells was done to classify according to the American Thoracic Society Guidelines. Concordance was checked between the diagnoses made on TBLB and BAL analysis. Results: In the present study, a total of 40 cases were included of which 13 (32.5%) cases showed neutrophilic, 16 (40%) cases showed lymphocytic, 5 (12.5%) cases showed eosinophilic and 6 (15%) cases showed normal cellular distribution on BAL cytology. Diagnoses on studying TBLB included nine cases of Nonspecific Interstitial Pneumonia, seven cases of Usual Interstitial Pneumonia, six cases of Bronchiolitis Obliterans Organising Pneumonia, three cases of Bronchiolitis, two cases each of pulmonary tuberculosis and granulomatous inflammation. There was one case each of actinomycosis, sarcoidosis, lung abscess and mucor mycosis. Normal histology was noted in seven cases. The sensitivity of BAL fluid analysis was found to be 84.84% and the concordance was 80%. The Kappa value obtained was 0.71 indicating good agreement/concordance between BAL cytology and TBLB. Conclusion: The data from the current study suggest that differential cell counts in BAL provide diagnostic information of fundamental importance in frequently occurring non-neoplastic lung diseases in the community.