An endoscope accessory comprises a flexible sheet wrapped around the endoscope shaft to form a flexible overtube. The overtube has an inflatable positioning ring just proximal to the tip of the endoscope or echoendoscope to secure the position of the overtube within the body cavity. The overtube also has a sealing band within the internal surface of the overtube that when inflated create a seal around the endoscope shaft. Another part of the device is the catheter with an occlusion balloon at its free end portion that is carried by the overtube and extends beyond the tip of the endoscope. Inflation of the positioning ring, sealing band and occlusion balloon defines an examination compartment within the body cavity at the tip of the endoscope that can be filled with air or water for improving the quality of the endoscopic examination with regular endoscope of echoendoscope.
