Fine needle aspiration cytology of lung lesions: a clinicopathological and cytopathological review of 150 cases with emphasis on the relation between the number of passes and the incidence of pneumothorax.

OBJECTIVE: The aim of this study was to review the lung fine needle aspirations (FNA) that were done in our hospital between January 1998 and April 2004. Interobserver agreement, sample adequacy and the relation between the number of passes and the occurrence of pneumothorax are presented. STUDY DESIGN: One hundred fifty cases of lung FNA from the department of pathology files were identified and the available specimens and patient charts were reviewed. The interobserver agreement was calculated. The relation between the number of passes and the subsequent development of pneumothorax was tested using Mann-Whitney U-test. RESULTS: The material of 132 patients (88%) out of 150 were retrieved and reviewed. There were 85 cases of non-small cell lung cancer (NSCLC) (64.4%), nine cases of small cell lung cancer (6.8%), five cases of metastatic cancer (3.8%) and 33 cases were reported negative for cancer (25%). The NSCLC included 36 cases of adenocarcinoma (27.3%), 32 cases of squamous cell carcinoma (24.2%), and 17 cases of large cell undifferentiated carcinoma (12.9%). The interobserver agreement k was 0.93, (95% CI 0.87-0.98). The majority of cases (95.5%) were considered adequate for interpretation. The charts of 138 patients (92%) were reviewed for postprocedure radiologically confirmed pneumothorax. Sixteen patients (11.6%) developed pneumothorax only three of whom (2%) required a chest tube for treatment. The number of passes was identified in 118 patients (85.5%). The number of passes did not have a statistically significant association with the development of a pneumothorax (P = 0.747). CONCLUSION: Fine needle aspirations to diagnose lung lesions is a safe procedure with a low incidence of pneumothorax. Its findings are reproducible with high interobserver agreement. Immediate adequacy evaluation and triage by a pathologist guarantees adequate sample in most instances. The number of passes was not associated with an increased incidence of pneumothorax.