A COMPARISON OF BIOPSY THROUGH A PARASTERNAL ANTERIOR MEDIASTINOTOMY UNDER LOCAL-ANESTHESIA AND PERCUTANEOUS NEEDLE-BIOPSY FOR MALIGNANT ANTERIOR MEDIASTINAL TUMORS

The various methods of treating the numerous types of anterior mediast inal neoplasms are undergoing refinements; however, prior to the comme ncement of any treatment, an accurate histologic diagnosis must be est ablished. We conducted a retrospective analysis of biopsies performed through a parasternal anterior mediastinotomy (PAM) on 21 patients wit h an anterior mediastial mass suspected of being malignant by computed tomography (CT) and other clinical information. Patients with possibl e localized thymomas were excluded. Mediastinotomy, which enables rela tively large tissue samples to be taken, was performed through the bed of the second or third costal cartilage under local anesthesia. In 19 of the 21 patients (90%), the histologic diagnosis made from the medi astinotomy biopsy was identical to the final diagnosis. Conversely; al though the tissue obtained from needle biopsy was sufficient for a his tologic diagnosis in 11 of 12 patients, the histologic diagnosis made from the needle biopsy was the same as the final diagnosis in only 5 o f 10 patients (50%), Thus, diagnostic accuracy was significantly highe r in the mediastinotomy biopsies than in the needle biopsies (P = 0.03 18), Moreover, the mediastinotomy biopsy specimens revealed subtypes o f lymphomas and germ cell tumors. All of the patients from whom a medi astinotomy biopsy had been taken began appropriate therapy without del ay according to the histologic diagnosis. These results suggest that t he PAM approach should be chosen as the preferred method of biopsy for suspected malignant anterior mediastinal tumors.