Benign DiseasesEUS has been used in the evaluation of various motor disorders [49], including scleroderma and achalasia. Various abnormalities of the esophageal wall, including thickening or replacement of various layers, have been described. These findings, however, are found inconsistently because artifacts can easily result when scanning the area around the lower esophageal sphincter. Oblique scanning, balloon compression, and rapid passage of the scope through the abnormal area can make accurate evaluation of the thickness of each layer in the GI wall difficult. However, when malignancy causes a disturbance of the 5-layer wall architecture in asymmetrical patterns, malignancy can usually be distinguished from primary achalasia. In 1 study [49], 6 of 36 patients with manometric signs of primary achalasia were found on EUS to have either malignant or benign tumors. In patients found to have benign submucosal tumors of the esophagus, manometric findings consistent with various motility disorders can be found in more than 50%. EUS therefore appears to be most valuable in finding abnormalities that may mimic primary motility disorders. Tumors causing pseudoachalasia can easily be detected with EUS. It should therefore be performed in patients in whom initial evaluations are not clearly diagnostic and there is suspicion that a tumor may exist. The inability of EUS to reliably differentiate inflammatory from malignant tissue causes problems in the evaluation of a smooth esophageal stenosis. There has been no clear demonstrated value of EUS in evaluating peptic esophageal strictures, Barrett's esophagus, or other reflux-related diseases [15]. EUS may have a role in directing repeat biopsy of suspicious areas when initial biopsies are negative, but, because of the low accuracy in differentiating inflammatory or fibrous tissue from malignant tissue, EUS will have a limited role in these diseases. Once a diagnosis of malignancy is made, however, staging will be as accurate as with other malignancies of the esophagus. |