Cytological, cell block and immunohistochemical analysis of spectrum of malignant pleural effusion with special reference to non-small cell lung carcinoma: A hospital based study of North East India

Abstract

Malignant pleural effusions (MPE) can result from primary malignancies of the pleura or from underlying intrathoracic or extrathoracic malignancies that reach the pleural space by hematogenous, lymphatic, or contiguous spread. Conventional smear and cell block (CB) technique is one of the oldest methods for the evaluation of body cavity fluids. The principal advantage of cell block over conventional smears are an additional yield of malignant cells and obtaining multiple sections for ancillary tests such as immunohistochemistry (IHC). This study is a hospital-based cross-sectional study which was conducted for a period of 14 months from June 2021 to July 2022 in a tertiary care centre of North East India. Among 277 pleural effusion specimens 11.91% cases were positive for malignancy.Lung carcinoma was the most common cause of malignant pleural effusion. Non-small cell lung carcinoma comprised majority of lung carcinoma cases. Adenocarcinoma was the most common subtype of NSCLC with female preponderance. Cytological diagnosis had a Sensitivity of 76.19%, specificity of 100% andAccuracy of 96.5%. Immunohistochemistry of lung carcinoma in cell block preparation revealed 77.77% cases of adenocarcinoma of lung were positive for TTF-1(P<0.018). Immuno-expression of P63 and P40 showed positive expression in both the cases of squamous cell carcinoma. Conventional smear and cell block method with application of immunohistochemistry will help us in accurate diagnosis of primary site of the tumour aiding early treatment especially in resources restricted hospitals.