Simple endometrial hyperplasia

Simple endometrial hyperplasia, abbreviated SEH, is an uncommon pre-malignant change of the endometrium. Like complex endometrial hyperplasia, it is subdivided into with atypia and without atypia.

General

• More common than simple endometrial hyperplasia with atypia.
• Very low risk for progressing to endometrioid endometrial carcinoma.

Microscopic

Features:

• Irregular dilated glands (with large lumens) - key feature.
  • Glands described as "animal shapes".
• Variation of gland size.
• No nuclear atypia.
  • Uniform columnar nuclei.
• Normal gland density (gland area in plane of section/total area ~= 1/3).
• +/-Nuclear atypia:
  • Loss of basal nuclear stratification.
  • Nuclear size variation.
  • Nuclear rounding.
    • Nuclei lacking atypical = uniform columnar nuclei.
  • Nucleoli.
  • Hyperchromasia or vesicular nuclei.

Notes:

• There are no universally accepted criteria for atypia. Different sources list different features.
• A proposal for atypia (all should be present):
  1. Increased NC ratio.
     • Atypical: ~ 1:2
     • Not atypical: ~1:3.
  2. Oval nuclei with small major axis to minor axis ratio.
     • Atypical: major axis:minor axis = <=2:1.
     • Not atypical: major axis:minor axis = >=3:1
       • NB: round nuclei: major axis:minor axis = 1:1.
  3. Small nucleoli (~1/5 the size of the nucleus).

DDx:

• Disordered proliferative phase.
• Complex endometrial hyperplasia - has increased gland-to-stroma ratio.
• Cystic atrophy of the endometrium - does not have proliferative activity.
• Benign endometrial polyp - has thick-walled blood vessels; simple endometrial hyperplasia should not be diagnosed in a polyp.

Images

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  Simple endometrial hyperplasia - low mag. (WC)

• 

  Simple endometrial hyperplasia - high mag. (WC)

www:

• Simple endometrial hyperplasia without atypia (webpathology.com).

See also

• Endometrium.
• Endometrial hyperplasia.