Transesophageal endoscopic ultrasound-guided biopsy of lesions in the mediastinum: A minimal invasive method for primary diagnosis of unknown mediastinal lesions and staging of lung cancer

Diagnosis of indeterminate mediastinal masses and staging of lung cancer poses a significant challenge. Transesophageal endoscopic ultrasound scanning (EUS) provides high resolution imaging of the mediastinum and offers the facility of fine needle aspiration or tru-cut biopsy under real-time ultrasound guidance. Accurate diagnosis of nodal involvement in lung cancer is pivotal to avoid unnecessary surgical exploration. The reported specificity of CT, MRI or PET is insufficient to exclude patients from curative management and mediastinoscopy or thoracoscopic sampling though specific requires general anaesthesia and hospital admission in addition to carrying 2-3% morbidity. EUS has a sensitivity of 60-90% and specificity of 70-100% in staging of lung cancer. For the staging of lung cancer, EUS has been found to be superior and specific as compared to CT, PET, mediastinoscopy as well as transbronchial aspiration. In other mediastinal lesions like tuberculosis or sarcoidosis, EUS is far more accurate in characterisation and obtaining tissue diagnosis than other contemporary modalities. EUS is thus emerging as the modality of choice is staging of lung cancer and diagnosis of mediastinal lesions.