Endometrial Hyperplasia

Endometrial hyperplasia: is an important cause of abnormal uterine bleeding, a result of a variety of disordered glandular and stromal growth patterns. Although endometrial hyperplasia per se is benign, hyperplasia in which there are atypical changes in cells (cellular atypia) are precancerous lesions. Similar to endometrial adenocarcinoma, hyperplasia is associated with hyperestrogenism.

Endometrial proliferative progression: endometrial patterns following unopposed oestrogen action

Weakly proliferative > Normal proliferative> Disordered proliferative

> Adenocarcinoma > Hyperplasia (> atypia)

Disordered proliferative endometrium: a focal change in which the total volume of the endometrium is not markedly increased; associated with…

• Mild Increase in gland : stroma ratio

• Glands may show some dilatation, budding, branching or irregularities of shape

• Mitoses are not as common as in normal proliferative endometrium

Classification: histologically there are two general categories of hyperplasia:

1. Low grade hyperplasias include:

   • Simple hyperplasia (cystic or mild hyperplasia), in which benign hyperplastic glands become cystically dilated (lined by tall columnar epithelium)

   • Complex hyperplasia (adenomatous), in which glands of varying sizes and shape may show budding and branching with marked crowding of glands (clusters - back to back)

[Note: terms simple or complex refers to the degree and nature of glandular proliferation]

2. High grade hyperplasias include:

• Atypical hyperplasia, in which the glandular complexity is accompanied by cellular atypia of the hyperplasic epithelium; cells lose polarity, enlarged nuclei, increased mitoses etc.

All these types produce abnormal uterine bleeding, but only atypical hyperplasia is associated with a significant frequency of progression to carcinoma.

Related risks: of progression to carcinoma…

Simple hyperplasia without atypia: minimal risk

Complex hyperplasia without atypia: <2%>

Simple hyperplasia with atypia: <10%>

Complex hyperplasia with atypia: 25-80% risk

Category: Gynecology Notes