PTEN immunohistochemical images of normal
(proliferative), unopposed estrogen exposed (persistent proliferative),
and frankly premalignant (EIN) endometria. Presence of PTEN
protein is indicated by a brown color, with circular PTEN-null glands
appearing pale with a light green counterstain.
Proliferative Endometrium: PTEN null glands are a small fraction
of all endometrial glands, appearing as isolated tubular glands to small
clusters of otherwise undistinguished glands. Cytology, gland
density, and gland size, are all identical to PTEN expresssing glands.
Endometrium (anovulatory, unopposed estrogens): PTEN null glands
undergo architectural changes exactly in parallel with those seen in PTEN
expressing glands exposed to estrogens for a protracted interval.
This includes a slightly increased gland density and increased average
gland size, without any PTEN-specific alterations in cytology.