- Abnormal uterine bleeding
- Focal endometrial thickening/mass with intact endometrium and a vascular stalk
Description
Endometrial polyps are benign growths of the endometrial lining of the uterus, consisting of glandular epithelium, stroma, and blood vessels. They can vary in size from a few millimeters to several centimetres and may be pedunculated or sessile. Endometrial polyps are common in reproductive-aged women but can occur at any age, including postmenopause.
Pathogenesis
The exact pathogenesis is not fully understood but is thought to involve hormonal factors, particularly estrogen, which stimulates endometrial growth. Polyps may arise from focal hyperplasia of the basal layer of the endometrium, and their growth is influenced by local vascular and growth factor abnormalities.
Epidemiology, Risk Factors & Associations
- More common in women aged 40-50 years.
- Risk factors include obesity, hypertension, tamoxifen use, and hormone replacement therapy.
- Associated with an increased risk of abnormal uterine bleeding and infertility.
Clinical Features
- Asymptomatic in many cases, discovered incidentally during imaging or surgical procedures.
- Abnormal uterine bleeding, including menorrhagia (heavy menstrual bleeding) or intermenstrual bleeding.
- Postmenopausal bleeding.
- Infertility or recurrent pregnancy loss.
Complications
- Most endometrial polyps are benign, but a small percentage may contain atypical hyperplasia or endometrial carcinoma, especially in postmenopausal women.
- Anaemia due to chronic blood loss in cases of heavy menstrual bleeding.
Pathological Features
Histopathology
- Macroscopic: Pedunculated or sessile growths projecting into the uterine cavity.
- Microscopic: Composed of endometrial glands and stroma, with a central fibrovascular core. Atypical polyps may show hyperplasia or malignancy.
Radiological Features
General Features
- Transvaginal ultrasound is commonly used for initial assessment, showing a well-defined echogenic lesion within the endometrial cavity.
- Saline sonohysterography enhances visualisation by distending the uterine cavity, allowing for better delineation of polyps.
- Hysteroscopy provides direct visualisation and allows for biopsy or removal of the polyp.
US
- Classic appearance in the proliferative phase is of a well-circumscribed homogenous echogenic mass or focal thickening within the endometrium supplied by a dominant feeding vessel on Doppler evaluation.
- Polyps may occasionally fill the endometrial cavity, mimicking diffuse thickening. Identification of the hyperechoic intact endometrium can help.
- Movement of the mass within the uterine cavity during transducer pressure is another feature suggesting intracavitary location.
- May be surrounded by endometrial fluid
- Doppler: Single feeding vessel in stalk – highly specific for endometrial polyp.
MR
- Intracavitary mass
- T1: Isotense to endometrium
- T2: Hypointense central fibrous core. Surrounding endometrial fluid may be seen. Intratumoural cystic spaces may be seen, may represent dilated glands with proteinaceous fluid.
- T1 Gd+: Enhancement may be homogenous or heterogeneous.
Differential Diagnosis
- Submucosal leiomyoma (fibroid): Can also cause abnormal bleeding but typically appear as well-circumscribed, hypoechoic masses (vs. hyperechoic) with areas of shadowing supplied by multiple vessels. May have a more spherical morphology (vs. oval and fusiform). Disrupts the endometrial-myometrial interface by stretching it.
- Endometrial hyperplasia: Diffuse or nodular thickening of the endometrium, without a discrete mass. No vascular pedicle.
- Adenomyoma: Focal adenomyosis (adenomyoma) are usually hypoechoic (vs. hyperechoic) and has a more permeative pattern of vascularity (vs. single vascular pedicle). Refractive shadowing, subendometrial cystic spaces may be present. Does not communicate with the endometrial cavity.
- Endometrial carcinoma: May present with similar symptoms and signs, underscoring the importance of biopsy in atypical or postmenopausal bleeding. If a post-menopausal woman has dysfunctional uterine bleeding, a thickness of > 5 mm is considered abnormal. If asymptomatic, a thickness > 8 mm is considered abnormal.
- Gestational trophoblastic disease: Often associated with hyperemesis due to extremely high β-hCG levels. 25% association with theca lutein cyst
- Intracavitary blood is usually mobile and avascular and may change with time.
Management
- Asymptomatic polyps in premenopausal women without risk factors for endometrial carcinoma may be monitored.
- Further imaging workup could include saline-infused hysterosonogram (SIS) or pelvic MRI. Further clinical workup might include hysteroscopy and/or endometrial biopsy.
- SIS should be performed within first 10 days of menstrual cycle in menstruating females to avoid risk of displacing a possible early pregnancy (implantation can only occur after 14 days). NSAIDs administered 1 hour prior for patient comfort.
- Symptomatic polyps, polyps in postmenopausal women, or those with atypical features should be removed, typically via hysteroscopic polypectomy.
- Histological examination of removed polyps is necessary to exclude atypia or malignancy.