Slide 1.5
This is a low-power image of a pituitary adenoma (right) and residual normal anterior pituitary (left), separated by a fibrous capsule (in the middle). Please note that the adenoma is composed of a uniform population of cells, while the residual normal pituitary gland is composed of a mixture of cells.

Slide 1.6
This is a high-power image of the pituitary adenoma itself. The cells are monomorphous, uniform, polygonal in shape. The reticulin network is decreased (this can be better appreciated on a reticulin stain). Cellular monomorphism and absence of reticulin network distinguish a pituitary adenoma from normal anterior pituitary gland. Please note that the functional status of an adenoma cannot be predicted from the histologic appearance.