Role of endoscopic ultrasound-guided fine-needle aspiration in lung and mediastinal lesions

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) was initially introduced for diagnosing gastrointestinal and pancreatic lesions, and later on for lung and mediastinal lesions. It can provide tissue diagnosis of lung cancer where bronchoscopy is non-diagnostic. It is a minimally invasive method for lymph node (N) and metastasis (M) staging of non-small cell lung cancer, and is helpful for tissue proof of mediastinal mass with unknown origin. Few data on this topic have been reported from Eastern countries. We report our experience of using EUS-FNA for tissue proof of lung and mediastinal lesions.

This was a retrospective analysis of prospectively collected data of 20 cases, with 21 EUS-FNAs of lung and mediastinal lesions (1 EUS-FNA performed on left adrenal gland) for tissue diagnosis and staging. With patients' informed written consent and fasting for 8 hours, EUS-FNA was performed with a linear echoendoscope using a 22- or 5-gauge needle and a syringe with 10-20 mL negative pressure. The cytology smear was fixed with 98% alcohol, while cell-block and tissue were sent for histology. There was no onsite cytopathologist. EUS-guided Tru-Cut biopsy was performed in 1 case. Malignancy was proven by FNA biopsy results, mediastinoscopy when performed, or by clinical course and follow-up.

Of the 20 cases, 19 were male and 1 was female; mean age was 63.9 ± 12.6 years. Median tumor size was 2.6 cm (range, 1.8-5.0 cm), and median number of punctures was 3 (range, 2-7). Eighteen EUS-FNA punctures were performed at the mediastinum, and 2 directly on lung mass. The size of the left adrenal metastasis for extramediastinal EUS-FNA was 1.2 cm. Of the 16 EUS-FNA-positive cases, 12 were for tissue diagnosis, 3 were for both tissue diagnosis and staging (N2 and M1 staging), and 1 was for N2 staging. EUS-FNA provided a tissue diagnosis in 14 cases where bronchoscopy was negative. In 16 positive EUS-FNAs, all except 1 had adequate tissue for FNA biopsy. The sensitivity, specificity, and diagnostic accuracy of EUS-FNA were 84.2%, 100%, and 85%, respectively.

EUS-FNA can diagnose lung cancer by confirmation of mediastinal lymph node metastasis, by direct puncture of lung tumor close to the esophagus. It is useful for lymph node (N) stations 5, 7, 8 and metastasis (M) staging in non-small cell lung cancer, and for the diagnosis of mediastinal mass of unknown etiology.