Slide 1

Is a low power photograph of the slide in your class set.  The mucosa "M", submucosa (SM), muscularis  propria (MP), and serosa are all readily apparent.  At this magnification you can see an adenocarcinoma that extends into the submucosa (double arrows).

Slide 2

The left panel shows a moderately differentiated adenocarcinoma arising from the mucosa.  The islands of malignant cells in the submucosa have invaded into lymphatic channels (arrows).

Higher magnification in the right panel shows that the gastric mucosa has been largely replaced by adenocarcinoma.  The malignant gland that is marked by the double arrows is seen at higher magnification in Slide 3.

Slide 3

Note the complex pattern of this malignant gland.  Whereas a benign gland is lined by a single layer of cells, the malignant gland is hypercellular.  This results in the stratification of malignant cells with the formation of an irregular, thickened gland wall.  Small, accessory glandular lumina form in the wall of the major gland to form the so-called "gland-within-gland" pattern.  Also note the irregular size and shape ("pleomorphism") of the nuclei of the malignant cells and the increased mitoses.