Benign and premalignant lesions of the endometrium

The most common benign tumors of the endometrium are endometrial hyperplasia and endometrial polyps. Endometrial hyperplasia is caused by an increased estrogen stimulation and manifests with irregular, often heavy vaginal bleeding. There are 2 types of endometrial hyperplasia: endometrial hyperplasia with atypia and endometrial hyperplasia without atypia. Diagnosis involves ultrasound (to assess the thickness of the endometrium) and biopsy (to assess atypia). Treatment of endometrial hyperplasia without atypia consists mainly of progestin therapy, while endometrial hyperplasia with atypia requires hysterectomy. Endometrial polyps are localized overgrowths of endometrial tissue that mainly affect postmenopausal women. Though usually asymptomatic, endometrial polyps can cause irregular vaginal bleeding and, in premenopausal women, infertility. Diagnosis is made with ultrasound or hysteroscopically. Treatment involves watchful waiting in asymptomatic patients and surgical removal in symptomatic patients.

Definition

• An abnormal thickening of the uterine lining caused by the proliferation of endometrial glands due to estrogen stimulation and insufficient progestin stimulation

Etiology

• Increased estrogen stimulation leading to excessive proliferation of the endometrium, e.g., due to
  • Follicle persistence in anovulatory cycles (e.g., perimenopause, PCOS)
  • Estrogen-producing ovarian tumors (e.g., granulosa cell tumors, theca cell tumors)
  • Hormone replacement therapy without progestin administration
  • Obesity
  • Tamoxifen therapy in postmenopausal women
• Lynch syndrome

Classification

Clinical features

• Vaginal bleeding (intermenstrual, postmenopausal, or constant bleeding)

Diagnosis

• Ultrasonography: to assess endometrial thickening (> 1.5 cm in premenopausal women; and > 5 mm in postmenopausal women) ^[3]
• Hysteroscopy-guided or blind endometrial biopsy (rarely dilation and curettage): for histological analysis ^[4]
• Laboratory measures: FSH, estradiol, testosterone

Treatment

The choice of treatment primarily depends on the presence of atypia and if menopause has occurred yet. ^[5]

• Definition: focal overgrowth of localized benign endometrial tissue
• Characteristics
  • Localized within the uterine wall, extends into the uterine cavity
  • Can be pedunculated or sessile, single or multiple, and up to many centimeters in size
  • May contain smooth muscle cells and/or blood vessels
  • Expresses both estrogen and progesterone receptors (estrogen stimulates growth) ^[6]
• Epidemiology: prevalence rises with age (most common in postmenopausal women) ^[6]
• Risk factors
  • Hypertension
  • Obesity
  • Tamoxifen ; or hormone replacement therapy (e.g., postmenopausal hormone therapy)
  • History of cervical polyps
  • Lynch syndrome
• Clinical features
  • Usually asymptomatic
  • Irregular menstrual bleeding, spotting, menorrhagia, and postmenopausal bleeding
  • Infertility, difficulty conceiving ^[7]
• Diagnostics
  • Transvaginal ultrasound
  • Hysteroscopy
  • Endometrial biopsy to rule out other conditions (e.g., endometrial hyperplasia, carcinoma)
• Treatment
  • Asymptomatic women: observation and follow-up
  • Symptomatic women: surgical removal (via hysteroscopy)
• Differential diagnosis
  • Endometrial hyperplasia
  • Endometrial carcinoma
  • Uterine leiomyoma
  • Also see “Differential diagnosis of dysmenorrhea and menorrhagia.”
• Prognosis: ∼ 0.5–4% of uterine polyps are premalignant or malignant ^[8]