Pleural fluid cytology samples in cases of suspected lung cancer: An experience from a tertiary care centre

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.

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.

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.

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.