Objective: Pleural effusion is present in some patients with lung carcinoma. This study was undertaken to evaluate the role of pleural fluid cytology in suspected cases of lung carcinoma.
Methods: In this prospective study, 86 cases of suspected primary lung carcinoma associated with pleural effusion were included. Cytomorphology of conventional smears was combined with LBC smears and a cytomorphological diagnosis was offered. An immunopanel of CK7, CK5/6, p63, TTF1, calretinin, and CD56 was applied on cell blocks. Additional immunochemical markers were performed based on clinical details and cytomorphology, wherever indicated.
Results: The mean age of the patients was 56.8 years. The female to male ratio was 2.1:1. Lung nodule/mass could be detected in 70.9% cases by CECT chest. Cytomorphology was evaluated in all the 86 cases and IHC was used to refine the cytomorphological diagnosis. After IHC along with clinico-radiological details, 61/86 (71%) cases were confirmed as metastasis from lung primary, 5/86 (5.8%) were diagnosed as metastatic adenocarcinoma of extrapulmonary origin, and 6/86 (7%) were metastatic SCC. A diagnosis of adenosquamous carcinoma was suspected in five cases. Other cases included small cell carcinoma (n = 2), large cell carcinoma (n = 2), large cell neuroendocrine carcinoma (n = 3), and mesothelioma (n = 1). One case remained "uncategorized" even after IHC.
Conclusions: Immunohistochemistry (IHC) performed on the pleural fluid sample can accurately diagnose and subtype primary lung carcinoma even in cases where radiology failed to identify a definite lung lesion. IHC can further help in delineating primary site in tumors of extrapulmonary origin. © 2017 Wiley Periodicals, Inc. Diagn. Cytopathol. 2017;45:195-201. © 2016 Wiley Periodicals, Inc.
Keywords: cytology; effusion; immunohistochemistry; pleural fluid.
© 2017 Wiley Periodicals, Inc.