Importance of the cell block technique in diagnosing patients with non-small cell carcinoma accompanied by pleural effusion

Background: Cytological examination of pleural effusions is very important in the diagnosis of malignant lesions. Thoracentesis is the first investigation to be performed in a patient with pleural effusion. In this study, we aimed to compare traditional with cell block methods for diagnosis of lung disease accompanied by pleural effusion. Materials and Methods: A total of 194 patients with exudative pleural effusions were included. Ten mililiters of fresh pleural fluid were obtained by thoracentesis from all patients in the initial evaluation. The samples gathered were divided to two equal parts, one for conventional cytological analysis and the other for analysis with the cell block technique. In cytology, using conventional diagnostic criteria cases were divided into 3 categories, benign, malignant and undetermined. The cell block sections were evaluated for the presence of single tumor cells, papillary or acinar patterns and staining with mucicarmine. In the cell block examination, in cases with sufficient cell counts histopathological diagnosis was performed. Results: Of the total undergoing conventional cytological analyses, 154 (79.4%)were reported as benign, 33 (17%) as malignant and 7 (3.6%) as suspicious of malignancy. With the cell block method the results were 147 (75.8%) benign, 12 (6.2%) metastatic, 4 (2.1%) squamous cell carcinoma, 18 (9.3%) adenocarcinoma, 5 (2.6%) large cell carcinoma, 2 (1%) mesothelioma, 3 (1.5%) small cell carcinoma, and 3 (1.5%) lymphoma. Conclusions: Our study confirmed that the cell block method increases the diagnostic yield with exudative pleural effusions accompanying lung cancer.