Evaluation of polyps by endoscopic ultrasonography (eus): implication for endotherapy

EUS is the single best imaging modality in precise visualization of the liv e layers structure of G.I. tract wall, space occupying lesion end surroundi ng structures. In case of "protruding lesion" into the G.I. lumen, the site of origin of the tumor can be easily determined by EUS, and then its natur e can be presumed (1). However, despite of these tiny details of the G.I. w all obtained by EUS, histology is still mandatory,especially when dealing w ith lesion suspected of malignancy(2). In case of sessile malignant "polypo id" lesion, Endoscopic Mucosal Resection (EMR) guided by EUS, could be cons idered in specific cases of selected patients. Conventional EUS transducer (7.5 and 12 Mhz) employed for this purpose is n ot sufficient for differentiating cancers invading the muscularis mucosae f rom those invading the sub-mucosa. A Miniature Ultrasonic Probe (20 and 30 Mhz) which can be used through the biopsy channel of an endoscope has recen tly been developed and is accurate in measuring such a superficial infiltra tion and in assessing regional lymph nodes allowing then an exact pre-treat ment staging. In patient not fitted for surgery, with a lesion less than 2 cm and involving less than half circumference of the lumen, EMR could be pe rformed according to the parietal infiltration (T), the nodal involment (N) and the related involved organs (Esophagus, Stomach, Colo-rectum). Conclusions: EUS may be usefull and sometimes is mandatory for assessing th e G.I. tract polyps before resection.