The diagnostic yield of pleural fluid cytology versus pleural biopsy in malignant pleural effusion

Abstract Background Malignant pleural effusion (MPE) is a common problem in neoplastic diseases. Studies showed that 42–77% of exudative effusions result from malignancy. Pleural fluid cytology revealed positive results in 60% of carcinomatous effusions and 30% of mesotheliomas. However, a pleural biopsy is performed for inconclusive cases. Aim To evaluate the diagnostic yield of pleural fluid cytology and image-guided percutaneous needle biopsy among patients with MPE. Patients and methods Our descriptive study included 56 patients. Pleural fluid analysis, including pleural fluid cytology and image-guided percutaneous needle pleural biopsy, was performed. Cytological and histopathological findings were evaluated. Results Patients had a median age of 63 years. Males represented 55.4%. Smoking history was noted at 53.6%. Effusion characteristics varied; most effusions were right-sided, yellow or hemorrhagic, and mainly consisted of lymphocytes. The effectiveness of the two diagnostic methods – cytology and image-guided biopsy – was compared. Among those tests, cytology detected malignancy at 37.5%, while image-guided biopsy identified malignancy at 87.5%. Five cases showed atypical infiltrates, and immunohistochemistry was performed to confirm malignancy. The diagnostic yield of pleural fluid cytology was evaluated in comparison with that of pleural biopsy. Conclusion Cytological examination of pleural fluid is a common initial diagnostic procedure in patients with suspected MPE. However, image-guided pleural biopsy is significantly more sensitive in detecting malignancy and is crucial for inconclusive cases.