Evaluation of ultrasonically guided biopsies of mediastinal masses.

Eighty patients with roentgenographic evidence of mediastinal abnormalities were examined with ultrasonography. Fifty-four lesions were malignant, and 26 lesions were benign. The histologic diagnoses were confirmed by ultrasonically guided fine needle aspiration/cutting needle (Tru-Cut) biopsy, surgical specimens, or transbronchial biopsy. There were no unique ultrasonographic features for diagnosis of specific tumors. Ultrasonically guided aspiration biopsies (UGAB) were performed in 44 of the malignant lesions and in 14 of the benign lesions (nine of the noncystic lesions and five of the cystic lesions). Cytologic diagnosis of malignancies was obtained in 34 (77 percent) of these 44 malignancies; however, accurate histologic classifications of malignancies were achieved in only 24 (55 percent). Accurate diagnoses were achieved in only three (33 percent) of the nine noncystic benign lesions. Ultrasonically guided cutting biopsies (UGCB) were performed in 24 malignant and five benign lesions. All attempts yielded satisfactory specimens for histologic diagnosis. Using UGAB and UGCB together, a positive diagnosis was achieved in 89 percent (39/44) of the malignancies, and accurate histologic diagnosis was achieved in 89 percent and 78 percent (7/9) in malignant and benign noncystic lesions, respectively. Correct histologic diagnosis with UGAB alone is lower in thymoma (55 percent [6/11]) and lymphoma (30 percent [3/10]) but higher in lung cancer (67 percent [8/12]) and metastatic cancer (78 percent [7/9]). There were no complications in this series. We conclude that ultrasonography with UGAB has a high diagnostic yield in diagnosing mediastinal tumors, and UGCB is necessary for thymic tumors, lymphoma, and benign lesions.