EUS-guided fine needle aspiration in mediastinal lymphadenopathy of unknown etiology

Background. EUS-guided fine needle aspiration (EUS-FNA) has significantly expanded the diagnostic capability of GI EUS. FNA technology can also be helpful in the diagnosis of non-GI disorders. The role of EUS-guided FNA in the diagnosis of mediastinal lymphadenopathy of unknown etiology has not been described. The aim of this study was to evaluate the diagnostic accuracy and impact on subsequent evaluation and therapy of EUS-FNA in mediastinal lymphadenopathy of unknown cause. Methods: Sixty-two patients (40 men, 22 woman; mean age 56 years, range 16-91 years) with mediastinal lymphadenopathy of unknown etiology underwent EUS-FNA at 6 tertiary referral centers. Presenting symptoms included the following: dysphagia, 6 patients; night sweats, 14; cough, 8; chest pain, 10; odynophagia, 10; fever, 6; weight loss, 8; and asymptomatic/abnormal radiograph, 12. A final diagnosis by EUS-FNA, surgery, autopsy, or long-term follow-up was available for all patients. EUS-FNA results were classified under 3 disease categories: (1) benign/infectious; (2) malignant pulmonary; and (3) malignant mediastinal (e.g., lymphoma, metastatic malignancy). Four EUS features were used as criteria for lymph node metastases: size greater than 1 cm, round shape, sharp border, and homogeneous/hypoechoic echo pattern. Results: Final diagnoses included benign/infectious lymph nodes, 26; malignant pulmonary, 24; and malignant mediastinal, 12. EUS-FNA established a tissue diagnosis in 56 of 62 patients (90%). EUS criteria for malignant lymph nodes were more frequently present in malignant pulmonary (mean 2.6 features) and malignant mediastinal (mean 2.8) than benign/infectious (mean 1.9) lymph nodes. EUS results influenced subsequent evaluation in 87% and therapy in 87% of patients. There was no complication of EUS-FNA. Conclusions: EUS-FNA in patients with mediastinal lymphadenopathy is safe and guides subsequent therapy in the great majority of cases. Transesophageal EUS-FNA of mediastinal lymph nodes provides minimally invasive tissue sampling, obviating the need for mediastinoscopy or bronchoscopy.