[The value of endoscopic ultrasonography in the study of submucosal tumors of the digestive tract].

Twenty-one consecutive patients with 24 possible submucosal lesions of the digestive tract were studied. Endoscopic ultrasonography (EUS) differentiated between 17 true positive submucosal tumors and 3 true negative extrinsic compressions. False positives were interpreted in 3 cases and in one patient no lesion was echoendoscopically observed (false negative). The sensitivity was 94%, the specificity 50% and the positive and negative predictive values were 82% and 75%, respectively. In conclusion, EUS may be the method of choice for the study of submucosal tumors since it allows visualization of the five layers of the wall of the digestive tract in which a tumor may originate, determination of its sonographic features, depth and exact size, in addition to the invasion of neighboring organs. Moreover, EUS may aid in collecting material for cytology and microscopy by fine needle aspiration puncture (FNAP) by EUS.