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ENDOMETRIAL THICKNESS
IN POSTMENOPAUSAL PATIENTS WITHOUT VAGINAL BLEEDING

Last modified: September 9, 2025

Main reference: ARRS 2025, SOGC 2024

Endometrium.jpg

Important Notes

  • On CT or MRI, heterogeneous endometrium or suspicion of focal mass

    • Endovaginal ultrasound recommended

    • Regardless of endometrial thickness

  • At endovaginal ultrasound, Bx recommended

  • Diffusely vascularized or heterogeneous endometrium

  • Complex fluid in the endometrial cavity

  • Endometrium ≥ 4 mm with risk factors (obesity, hypertension, genetic risk – e.g. Lynch syndrome)

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Additional Notes

  • Endometrial neoplasia presents with vaginal bleeding in 90%

    • Incidental discovery of neoplasia is rarer

  • Asymptomatic postmenopausal women without hormone therapy regardless of their endometrial thickness = low risk of neoplasia

    • Prevalence of endometrial neoplasia: 0.62%

    • Prevalence of atypical endometrial hyperplasia: 0.59%

  • Endometrium >11 mm in asymptomatic patient

    • Assuming 15% neoplasia prevalence, 6.7% cancer risk

    • Similar risk in women with abnormal vaginal bleeding and endometrial thickness >5 mm (7.3%)

  • Endometrium ≤11 mm in asymptomatic patient

    • Risk of neoplasia or atypicality = 0.0002%

  • Risk factors for neoplasia in asymptomatic patients

    • BMI >26

    • Late menopause

  • No ultrasound follow-up for patients under tamoxifen*

  • DDx endometrial thickening in postmenopausal women

    • Cystic atrophy

      • Association with Tamoxifen

    • Polyp

      • Echogenic mass with vascularized pedicle

      • Risk of malignancy 1.3%

      • If vaginal bleeding: 10X more risk of neoplasia and 2X more risk of pre-cancerous cells

      • Risk factors for pre-cancerous or neoplastic lesions: >18 mm

  • Endometrial hyperplasia

    • Management according to biopsy results

    • Atypical endometrial hyperplasia: more aggressive management and follow-up

    • Absence of atypia: reassurance

  • Endometrial carcinoma

    • No improvement in survival by screening asymptomatic women

Definitions

Endometrial thickness

  • Exclude fluid in the endometrial cavity

  • Ultrasound

    • Sagittal view through the endovaginal route

    • Maximum thickness, including both layers (on either side of the endometrial cavity)

  • CT C+

    • Sagittal reconstruction

    • Maximum thickness of the hypodense component

  • MRI

    • Sagittal T2

    • Maximum thickness of the hyperintense component

Figures

ARRS 2025.jpg

Figure 1. ARRS 2025 Recommendation

SOGC 2025.jpg

Figure 2. SOGC 2025 Recommendation

References

  1. Baumgarten, Deborah A. “The Incidentally Thickened Endometrium in Postmenopausal Women.” Roentgen Ray Review, vol. 1, no. 1, 1 Mar. 2025. doi: 10.2214/r3j.24.01023.

  2. Wolfman W, Bougie O, Chen I, Tang Y, Goldstein S, Bouteaud J. Guideline No. 451: Asymptomatic Endometrial Thickening in Postmenopausal Women. J Obstet Gynaecol Can. 2024 Jul;46(7):102591. doi: 10.1016/j.jogc.2024.102591.

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