Endometrium

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The endometrium is typically biopsied because of abnormal bleeding.

Indications

Biopsies done for bleeding:

  • Too much bleeding (if premenopausal) - AUB = abnormal uterine bleeding.
  • Post-menopausal bleeding.
  • Dysfunctional uterine bleeding AKA DUB - may get D&C if they fail medical management.[1]
    • DUB is diagnosed if other causes of bleeding are excluded.

Normal microscopic findings

  • Endocervical glands are commonly seen, as is endocervical mucous.
    • This is 'cause the gynecologist scrapes some off on the way in or out.

Endocervical glands vs. Endometrial glands

Endocervical

  • Less hyperchromatic.
  • Nuclei round & small.
  • Cell borders usually well-defined.

Endometrial

  • More hyperchromatic.
  • Nuclei columnar.

A simple approach

Low power

  1. Decide whether you're look at endometrium.
  2. Gland-to-stroma ratio normal?
  3. Glands round?
    • Round is normal.
    • Irregular - may be seen in menses, endometrial hyperplasia, disordered proliferative endometrium.
  4. Glands pseudostratified?
    • Pseudostratified glands are normal in the proliferative phase, hyperplasias, malignancy.
  5. Balls of cells?
    • Blue - likely menstrual (stromal condensation).
    • Pink - consider leiomyoma, squamous morules (associated with endometrial hyperplasia).

High power

  1. Mitoses present in the glands?
    • Present in the proliferative phase, hyperplasias, malignancies.
  2. Mitoses present in the stroma?
    • Present in the proliferative phase, hyperplasias, malignancies.
  3. Mucous present in the glands?
    • Present in the secretory phase.
  4. Inflammatory cells present?
    • Some are normal during menses.

Endometrial polyp

Epidemiology

  • Very common.

Microscopy

Features:[2]

  • Large blood vessels (muscular) - key feature.
  • Fibrotic stroma - key feature.
  • Polypoid shape - epithelium on three sides.
    • May not be seen... as polyp is fragmented on removal.

Notes:

  • Endometrial glands may be out of phase with surrounding endometrium.
    • Often proliferative.
  • +/-Cystic dilation of glands.
  • Cellular stroma.

Dating endometrium

Proliferative phase

  • Glands: straight, tubular, tall pseudostratified columnar cells, mitotic figures, NO vacuolation, NO mucus secretion.
    • Key features: pseudostratification, mitoses.
  • Stroma: cellular stroma (spindle cells), mitoses.

Note:

  • Proliferative phase = folicular phase.
    • Gynecologists prefer the ovarian descriptor, i.e. follicular phase; pathologists go by what they see, i.e. proliferative endometrium.

Secretory phase

  • Early secretory phase - post-ovulatory day 1-5:
    • Glands: secretory vacuoles.
      • First basal to the epithelial nuclei (infranuclear vacuoles).
      • Then apical to the epithelial nuclei (supranuclear vacuoles).
  • Mid secretory phase - post-ovulatory day 6-8:
    • Glands: Mucus in glands.
    • Stroma: Edema (empty space around the glands).
  • Late secretory phase (beginning) - post-ovulatory day 9-12:
    • Stroma:
      • Spiral arterioles.
      • Predecidual changes -- mnemonic NEW:
        1. Nucleus central.
        2. Eosinophilic cytoplasm key feature (may be subtle to the novice).
        3. Well-defined cell borders.
  • Premenstrual

General refs.: [4][5]

Notes:

  • Secretory phase = luteal phase.
    • Gynecologists prefer the ovarian descriptor, i.e. luteal phase; pathologists go by what they see, i.e. Secretions in the (endometrial) glands.
  • When the patient is >40 years, some advocate the use of the term proliferative type endometrium (instead of the term proliferative endometrium).[6]
  • Stromal condensation (stromal balls) - premenstrual - stromal cells tightly packed together; nuclei molded together like in small cell tumours.[7]

Abnormalities of endometrium

Disordered proliferative phase

  • Association: anovulation.

Features:[8]

  • Proliferative type endometrium with:
    • Cystic dilation of glands without secretions.
  • +/-Stromal condensation -- balls of stromal tissue, aka "blue balls" (due to breakdown of endometrium).

Notes:

  • Proliferative phase endometrium:
    • Glands: straight, tubular, tall pseudostratified columnar cells, mitotic figures, NO vacuolation, NO mucus secretion, abundant mitoses.
    • Stroma: cellular, stroma (spindle cells), mitoses.

Endometrium of a woman taking OCP

Features:[9]

  • Inactive glands (round/ovoid glands, simple cuboidal epithelium, no mitoses).
  • Stroma decidualized -- mnemonic NEW:
    • Nucleus central.
    • Eosinophilic cytoplasm.
    • Well-defined cell borders.

Image: Endometrium of woman on an OCP (WC).

Postmenopausal women

  • If a woman is truly postmenopausal, mitoses in the glandular epithelium is pretty much always pathologic.
    • Exception is inflammation... e.g. the person has had several biopsy attempts and was seeded with pathogens.

Endometrial hyperplasia

Can be thought of as a precursor lesion for endometrial carcinoma.

Endometrial carcinoma

Endometrial cancer is the common gynecologic malignancy (in the USA).[10]

See also

References

  1. URL: http://emedicine.medscape.com/article/257007-treatment. Accessed on: 15 July 2010.
  2. URL: http://www.pathologyoutlines.com/uterus.html#endopolyp.
  3. TC. 22 June 2009.
  4. Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease (7th ed.). St. Louis, Mo: Elsevier Saunders. pp. 1081. ISBN 0-7216-0187-1.
  5. Tadrous, Paul.J. Diagnostic Criteria Handbook in Histopathology: A Surgical Pathology Vade Mecum (1st ed.). Wiley. pp. 237. ISBN 978-0470519035.
  6. GAG. Jan 2009
  7. GAG. 6 Oct 2009.
  8. Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease (7th ed.). St. Louis, Mo: Elsevier Saunders. pp. 1080 and 1082. ISBN 0-7216-0187-1.
  9. Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease (7th ed.). St. Louis, Mo: Elsevier Saunders. pp. 1082. ISBN 0-7216-0187-1.
  10. Lu KH (April 2009). "Management of early-stage endometrial cancer". Semin. Oncol. 36 (2): 137–44. doi:10.1053/j.seminoncol.2008.12.005. PMID 19332248.