Fine-needle aspiration cytologic technique for lung cancer has a high potential of malignant cell spread through the tract

Background: Fine-needle aspiration cytologic technique (FNAC), a method to detect malignancy for undetermined pulmonary nodules, may have a high potential to spread malignant cells from the tumor to the pleural cavity. Objective: The authors assessed malignant cell spread through the needle tract following FNAC for peripheral lung carcinoma. Materials and methods: Lung lobes resected from 20 patients during the treatment of lung carcinoma were examined. The visceral pleura over the lung carcinoma was irrigated by heparinized saline solution to clean the surface, and then irrigated before FNAC and irrigated following FNAC to collect cells on the visceral pleura, FNAC was performed once for each tumor. Papanicolau's method was employed for cytologic examination. Results: There were 15 specimens of adenocarcinoma, 4 specimens of squamous cell carcinoma, and 1 specimen of atypical carcinoid. The maximum diameter of the specimens ranged from 10 to 60 mm (median, 25 mm), Pleural indentation was observed in 15 samples. All results of FNAC were positive and matched the histologic diagnosis. Pre-FNAC specimens revealed a positive malignancy rate of 10% (2 of 20), but post-FNAC specimens had a rate of 60% (12 of 20; p = 0.002) Conclusion: FNAC has the potential to spread malignant cells to the pleural space. Further study is needed to determine the clinical significance of the spread of malignant cells in the pleural space.