Endoscopic ultrasonography for esophageal and gastric mass lesions.

Endoscopic ultrasonography is a relatively new and evolving imaging modality incorporating endoscopy and ultrasonography into one comprehensive examination of the gut wall. Its principal indication has been the locoregional staging (T and N) of gastrointestinal tumors, particularly of the esophagus and stomach. Accuracy of conventional radiographic modalities (computed tomography and magnetic resonance imaging) has been disappointing (50-60%). Alternatively, the staging accuracy of the depth of tumor penetration (T stage) approaches 85-90% in most series, whereas that for lymph node assessment (N stage) has been in the 70-80% range. The precise stage of upper gastrointestinal neoplasms provides accurate pretreatment assessment of the patient's prognosis and may influence therapeutic decisions. Endosonography is also the diagnostic modality of choice in the evaluation of submucosal tumors. It can demonstrate size, layer of origin, and, by its echo texture, can accurately predict etiology of the neoplasm. The only limitation may be in the differentiation of benign from malignant smooth muscle tumors.