Role of mediastinoscopy in the diagnosis of mediastinal masses.

In order to assess the diagnostic efficiency of mediastinoscopy in patients with undiagnosed mediastinal masses, a retrospective review was undertaken of the results obtained in a consecutive series of 42 patients presenting over a 5-year period. In 28 (67%) patients, a tissue diagnosis was made. Ten (24%) patients underwent a negative mediastinoscopy but were found to have significant pathology on further investigation (eight in a location outside the range of conventional mediastinoscopy). Four (10%) patients had negative findings and were confirmed to have no significant pathology on further investigation and follow-up. Overall, mediastinoscopy had a sensitivity of 74%, a specificity of 100% and an accuracy of 76%; however, for lesions within the range of mediastinoscopy, the sensitivity was 93%, the specificity 100% and the accuracy 94%. The predictive value of a negative examination was 66%. Mediastinoscopy is a valuable technique in the diagnosis of mediastinal masses but, because of the low predictive value of a negative examination, further evaluation, including thoracotomy if necessary, is still indicated if mediastinoscopy is unhelpful.