Excision of half of the pylorus: Because the elderly Mr. White had a tumor in the lower part of his stomach, a hemipylorectomy had to be performed immediately, and Mr. White underwent the operation very well.

The "pylorus" is a thick muscular ring (sphincter) surrounding the outlet of the stomach into the duodenum.

It closes to prevent unduly large pieces of food from leaving, thus enabling stomach acid and enzymes to break them down further.