Endometrial Thickening

Endometrial thickening is an increase in endometrial thickness on ultrasound beyond the expected range for age and cycle phase. It is a finding, not a diagnosis.

• Causes are polyps, hyperplasia, cancer, tamoxifen effect, retained tissue, pregnancy, fibroids, and normal secretory phase.
• In postmenopausal women with bleeding, a thickness above 4 mm needs tissue sampling.
• In premenopausal women, interpretation depends on cycle day.

Postmenopausal bleeding, heavy or irregular periods, intermenstrual bleeding, or no symptoms.

• The pelvic examination is usually normal.
• Differential diagnosis: endometrial polyp, endometrial hyperplasia, endometrial cancer, submucosal fibroid, tamoxifen-related change, retained products of conception, endometritis, normal secretory endometrium.
• Complications: missed hyperplasia or cancer, anaemia, repeated investigation.

Diagnosis is by transvaginal ultrasound, with tissue sampling when the thickness or symptoms require it.

• Transvaginal ultrasound measuring the double-layer thickness in the midline.
• Endometrial sampling with a Pipelle or by dilatation and curettage for postmenopausal bleeding with thickness above 4 mm, and for asymptomatic postmenopausal women with thickness of 11 mm or more, or with risk factors.
• Hysteroscopy with directed biopsy for focal lesions, a non-diagnostic sample, or persistent bleeding.
• Pregnancy test; full blood count; thyroid function; cervical screening.
• In premenopausal women, repeat ultrasound in the first week after menses.

Treatment follows the histology found on sampling.

• Supportive: review of drugs (tamoxifen, unopposed oestrogen); weight loss; menstrual or bleeding diary; explanation.
• Pharmacological: management follows the diagnosis. Atrophic endometrium or normal histology: no drug. Hyperplasia without atypia: levonorgestrel 52 mg intrauterine system for at least 6 months, or medroxyprogesterone acetate 10 mg oral daily for 6 months. Atypical hyperplasia or cancer: surgery. Anaemia: ferrous sulphate 200 mg oral 8-hourly, continued for 3 months after haemoglobin normalises. Tranexamic acid 1 g oral 8-hourly for up to 4 days (maximum 4 g in 24 hours) for heavy bleeding.
• Procedures: hysteroscopy with polypectomy or resection of focal lesions; dilatation and curettage if hysteroscopy is not available; hysterectomy for atypical hyperplasia, cancer, or recurrent bleeding.
• Special groups: in women on tamoxifen, sample the endometrium for any bleeding and do not screen the asymptomatic. In women with Lynch syndrome offer yearly endometrial sampling.
• Red flags: recurrent postmenopausal bleeding, thickness of 11 mm or more after menopause, irregular intracavitary lesion, weight loss, pelvic mass.
• Follow-up: review histology at 1 to 2 weeks; repeat ultrasound and sampling at 3 to 6 months after treatment for hyperplasia.