Adequacy of Cytologic Samples by Ultrasound-Guided Percutaneous Transthoracic Fine-Needle Aspiration Cytology of Peripheral Pulmonary Nodules for Morphologic Diagnosis and Molecular Evaluations: Comparison With Computed Tomography-Guided Percutaneous Transthoracic Fine-Needle Aspiration Cytology

Context.— Fine-needle aspiration cytology (FNAC) of pulmonary nodules is usually guided by computed tomography (CT), whereas ultrasonography (US) is generally considered not applicable for such purposes. Objective.— To evaluate the clinical applicability and diagnostic utility of US-guided transthoracic FNAC of peripheral pulmonary nodules. Design.— Ultrasonography-guided transthoracic FNAC was obtained from 40 selected patients with peripheral, subpleural, and paravertebral pulmonary nodules. Air-dried and Diff-Quik–stained smears were used for rapid on-site evaluation; additional smears were alcohol fixed for Papanicolaou staining. Cell blocks were set up for immunocytochemical and molecular studies; in 2 cases, a flow cytometry evaluation was also performed. The series was compared to 40 CT-guided pulmonary FNAC samples from patients with pleural, peripheral, and paravertebral pulmonary nodules, to evaluate differences in terms of diagnostic rate, time of execution, safety, and cost. Results.— The US-guided FNAC samples had results that were adequate and representative in 95% of cases. No significant differences were observed between the 2 groups in terms of diagnostic rate, number of passes, and cellularity of both smears and cell blocks. The mean time needed for the execution of US-guided FNAC was 13.1 minutes, whereas the mean time for CT-guided FNAC was 23.6 minutes. Thus, US-guided FNAC was significantly more rapid than CT-guided pulmonary FNAC. Because pneumothorax occurred in 1 individual who underwent US-guided FNAC and in 9 who underwent CT-guided FNAC, we might conclude that US-guided FNAC is a significantly safer procedure. Finally, comparing the costs of both procedures, US-guided FNAC is less expensive. Conclusions.— Our experience showed an elevated clinical applicability and diagnostic utility of US-guided transthoracic FNAC for selected pulmonary nodules.