Corroboration of Fine Needle Aspiration Cytology Findings With Cell Block Study of Malignant Lung Lesions Using Immunostains (Ttf1, Napsin A, P40 and Chromogranin A).

Abstract

Background: Malignancy of the lung has been rising steadily worldwide and exact sub typing has become a necessity for targeted therapy. FNAC alone has its limitations in sub categorization of lung malignancy because of lack of architecture. Cell block preparation from FNAC material with immunohistochemistry panel would supplement the FNAC nding. Objectives: To determine the utility of cell block study using immunostains (TTF 1, Napsin A, p40 and Chromogranin A) in corroborating the ndings of FNAC in the study of malignant lung lesions. Materials and methods: A hospital based cross sectional study was done on the FNAC sample from lung masses followed by cell block study and immunohistochemical staining for (CHROMOGRANIN A, NAPSIN A, p40, TTF1). Data was analyzed using IBM SPSS statistics version 21 Software. Results: A total of 32 (54.2%) cases were found malignant and 27 (47.3%) cases were found benign. A total 59 cell block were prepared from 32 cases positive for malignancy (PFM) and 27 cases negative for malignancy(NFM). After cell block and immunohistochemical studies, 2 benign lesion were recategorized as malignant and 3 malignant cases recategorized as benign lesion. There was a substantial agreement found between FNAC diagnosis and IHC diagnosis as in both cases the kappa value (฀ coefcient) were found to be 0.747 (between 0.61 - 0.80). Conclusion: The cell block from the aspirated material revealed further architectural and immunohistochemical features which not only conrmed the FNAC diagnosis but helped to recategorize 2 benign and 3 malignant lesion.