AN UNUSUAL HETEROTOPIA OF PYLORIC GLANDS OF THE STOMACH WITH INVERTEDDOWNGROWTH

A rarely reported, large heterotopia of gastric glands in the submucos al layer of the stomach is observed in a 79 year old Japanese man with early gastric cancer. Histologically, it consists of marked hyperplas ia of benign foveolar-type epithelia and tubular glands which instead of growing upwards grow downwards into the submucosa. Immunohistochemi cally, many gastrin-positive G cells are observed within it, indicatin g the existence of independent pyloric-type glands from the surroundin g mucosa with intestinal metaplasia. Muscle actin-positive fascicles, derived from the muscularis mucosae, are demonstrated to branch into i t and to encapsulate it. This result suggests that the present lesion may not represent a truly submucosal ectopic location, but an inverted downgrowth of the mucosa into the submucosa, thus resembling an inver ted polyp of the colon. An awareness of this unique lesion is importan t in order that it not be mistaken for a submucosal extension of the p rimary adenocarcinoma.