Diagnosis, localization and evaluation of malignancy of heart and mediastinal tumors by conventional and transesophageal echocardiography.

Transesophageal echocardiography is well established in detecting and diagnosing heart tumors. In contrast, its role in assessing presence, growth and evidence of malignancy of tumors originating from the mediastinal site remains widely uncertain. In a prospective and investigator-blind study, we evaluated 72 consecutive patients with cardiac and/or mediastinal tumor lesions to assess the diagnostic impact of transthoracic and transesophageal echocardiography in determining localization, growth and malignancy. All tumor lesions were diagnosed and carefully evaluated by computer tomography and/or magnetic resonance imaging prior to the study. Biopsy demonstrated a malignant tumor in 49 patients and a benign tumor in 23 patients. Transthoracic and transesophageal echocardiography were equally effective in visualizing tumors of the heart in 24 patients (92% vs 100%; N.S.). Tumors originating from the mediastinum were 2.9 times less likely to be detected by the transthoracic approach (p < 0.001). In these patients, transesophageal echocardiography was also superior in diagnosing myocardial infiltration (18 vs 4 patients, p < 0.001) and invasion or intracardiac growth of the tumor (13 vs 6 patients, p < 0.05). When compared to histological findings, transesophageal echocardiography predicted malignancy from the presence of tumor spread both in- and outside the heart, infiltration and invasion in 21/49 patients (43%), a false positive result was obtained in only 1/23 patients with a benign tumor. Conventional echocardiography predicted malignancy in only 4/49 patients (8%, p < 0.005). In conclusion, transesophageal echocardiography is increasingly used in patients with suspected mediastinal tumor lesions. Our study demonstrates, that transesophageal echocardiography is effective and superior to the conventional approach in predicting localization and growth of mediastinal tumors, as well as in accessing evidence of malignancy of the tumor.