These two images show a papilla or Ampula of Vater that has been "cut" or undergone a sphincterotomy; subsequent is cannulation of papilla and bile duct. 

A guide wire can be placed in the bile duct to allow access for additional maneuvers, such as balloon sweeps, obtain brushing samples, or placement of biliary stents. A balloon catheter can be passed into the bile duct with the balloon deflated, then once the catheter is pushed up the bile duct, the balloon can be inflated and pulled down the bile duct dragging out any retained stones. 

This pair of images here show temporary biliary stents in the papilla allowing drainage of bile out of the bile duct. The stent on the left is placed deeply, with only a flap extruding. The one on the right has migrated partially out of the bile duct. It was removed to allow place a permanent metal stent in a patient with incurable pancreatic cancer whose bile duct needs to be kept open to allow drainage since the patient is not a candidate for curative surgery of the pancreatic tumor.

This pair of images demonstrates what a metal stent looks like in the papilla providing drainage of the bile duct in patient with cancerous obstruction of the bile duct (pancreatic cancer in this case). 

The above two photos are of the same polyp, the picture on the left was taken with standard light endoscopy, the one on the right is taken after switching the light wave to narrow band imaging (NBI) mode. This feature available on the newer endoscopes adds greater detail to the image that can help assess if a polyp, growth or lesion may be cancerous of precancer in nature.

The above photos are of benign precancerous polyps under the microscope. Both are tubular adenomas. There are redundant foldings of colon glandular cells. Compared to colon cancer, the glandular cells are still organized and have normal nuclei. Cancer cells rebel and expand, invade and have "angry" enlarged and much darker nuclei. An example of colon cancer under the microscope is below.

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