EUS Guided Transesophageal FNA in the Evaluation of Non-Esophageal Cancer Related Mediastinal Lesions

Abstract

Background: Endoscopic ultrasound (EUS) with fine needle aspiration (FNA) is a recognized method to assess and biopsy posterior mediastinal lesions. The benefit of EUS evaluation of mediastinal nodal involvement for esophageal cancer has already been established. Aim: The aim of this study was to investigate whether EUS would provide accurate assessment of non-esophageal cancer related mediastinal lesions and whether transesophageal EUS guided FNA would be an effective method in obtaining tissue diagnosis with minimal risks. This information will be used to help guide future endoscopic practices when approaching mediastinal lesions in patients with non-esophageal cancers. Methods: The medical records at MD Anderson Cancer Center were retrospectively reviewed for non-esophageal cancer patients who underwent EUS guided FNA for mediastinal lesions for diagnosis or staging evaluation during the period from Apr. 2005 - Aug. 2006. Results: A total of 13 consecutive patients were identified. All procedures were performed by one endosonographer. The mean age of patients was 64 years. EUS guided FNA was able to provide an accurate assessment of mediastinal lesions in 11 of 12 patients (sensitivity 91%; specificity 100%; PPV 100%; NPV 50%). A diagnosis of benign granulomatous disease (sarcoidosis) was made in 2 cases. A diagnosis of malignancy was successfully excluded in 1 case (reactive lymph node). A diagnosis of a malignancy was successfully established in 8 cases (4 non-small cell lung cancer; 3 metastatic cancer [renal, breast, melanoma]; 1 follicular adenomatous thyroid neoplasm). In the last patient with non-small cell lung cancer, FNA of a subcarinal lymph node was found to have histologic findings in keeping with reactive lymphadenopathy. The lymph node lacked malignant features but suspicious uptake was noted on PET scan. Subsequent surgical exploration two weeks later revealed 3 of 5 subcarinal lymph nodes to be positive for non-small cell lung cancer. No immediate complications were encountered in any of the cases. EUS FNA results influenced subsequent treatment decisions in all patients. FNA was not performed in one patient due to the presence of large esophageal varices; a subsequent diagnosis of histoplasmosis was established during mediastinoscopy. Abnormal PET scan was reflective of FNA pathology (malignancy or inflammatory condition) in 8 of 9 cases (sensitivity 88%; specificity 100%). Conclusions: Our results suggest EUS guided transesophageal FNA is an accurate, safe and effective method by which to assess posterior mediastinal lesions in non-esophageal cancer patients.