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endometrial hyperplasia

Saturday 29 January 2005

endometrial hyperplasia ; endometrial glandular hyperplasia


Definition: Endometrial hyperplasia is defined as endometrial proliferation with an increase in gland to stroma ratio (from 2:1 to 3:1). It is divided into simple hyperplasia (with or without atypia) and complex hyperplasia (with or without atypia) according to the WHO Classification.

Endometrial hyperplasia is an example of abnormal hormone-induced hyperplasia. After a normal menstrual period, there is a rapid burst of proliferative activity that is stimulated by pituitary hormones and ovarian estrogen.

In regards to endometrial hyperplasia - simple hyperplasia is non-branching, complex is branching. Atypia refers to the cellular characteristics.




- simple / complex

  • If the hyperplastic glands are not branching, the lesion is "simple".
  • If the hyperplastic glands are branching, the lesion is "complex".
  • Complexity carries a low risk of development of adenocarcinoma.

- No atypia / Atypia

  • Simple hyperplasia with atypia has an increased risk of adenocarcinoma.


- simple endometrial hyperplasia

  • simple endometrial hyperplasia with atypia

- complex endometrial hyperplasia


- simple endometrial hyperplasia without atypia
- simple endometrial hyperplasia with atypia
- complex endometrial hyperplasia without atypia

  • There is no evidence of invasion.
  • The basement membrane is intact around the glands and there is no desmoplastic response.
  • There is an overgrowth of endometrial glands, making this hyperplasia.
  • The glands are branching so the lesion is complex.
  • If they were non-branching, it would be classified as simple hyperplasia.
  • The cells are not dysplastic / atypical : complex hyperplasia without atypia.
  • It carries an increased risk of developing adenocarcinoma.

- complex endometrial hyperplasia with atypia

Differential Diagnosis

- artifacts / compression artifact
- endomatrial cystic atrophy
- endometrial polyp
- endometritis
-  metaplasia of the endometrium
- normal endometrium
- disordered proliferative endometrium
-endometrial stromal / glandular breakdown
- metaplastic changes / metaplasia

  • squamous and morular metaplasia
  • surface syncytial and eosinophilic metaplasia

- uterine endometrioid adenocarcinoma FIGO grade 1

  • Degree of atypia between the two is usually similar
  • AH / EIN should NOT have:
    • Cribriforming, confluent glands
    • Labyrinthine intraluminal connections
    • Areas of purely solid epithelium
    • Stromal alteration suggesting invasion - desmoplasia (myofibroblasts, edema, inflammation) or necrosis (intervening endometrial stroma replaced by pools of neutrophilic debris)

See also

- endometrial biopsy
- endometrial anomalies
- glandular hyperplasia