Yield of pleural cytology and macroscopic pleural invasion in metastatic pleural effusion

Introduction : Diagnostic sensitivity of pleural fluid (PF) cytology is 40-60% and is related to sample size and cytologist9s experience. Pleural extension could be a factor. We assessed PF cytology yield in relation to pleural invasion. Method : Medical records of 288 patients were reviewed. PF cytology, reported appearance during thoracoscopy and malignant diagnosis were inclusion criteria. Mesothelioma was excluded. Results : NSCLC and breast cancer were most frequent etiologies . 56% of patients had positive PF cytology. Thoracoscopy reported parietal pleural invasion in 97% of subjects. 81% of patients with positive cytology had visceral pleural invasion, while only 30% of those with negative cytology . Conclusion : PF cytological yield is significantly higher in patients with visceral pleural invasion. Positive PF cytology might be associated with more advanced disease.