What Are Endometrial Polyps
Endometrial polyps are localized, benign overgrowths of the endometrial lining that project into the uterine cavity, composed of glandular tissue, stroma, and a vascular core with thick-walled vessels. 1
Structural Composition
Endometrial polyps consist of several key tissue components:
- Glandular epithelium - endometrial glands that may be functionally responsive or inactive
- Stromal tissue - fibrous connective tissue framework
- Vascular core - characteristic thick-walled blood vessels that distinguish polyps from normal endometrium
- Connective tissue elements - providing structural support 2
These growths represent localized hyperplastic lesions rather than diffuse endometrial thickening, making them distinguishable from other endometrial pathologies 1.
Clinical Significance
While often asymptomatic, endometrial polyps can cause:
- Abnormal uterine bleeding - the most common presenting symptom, particularly postmenopausal bleeding 2, 3
- Infertility - polyps are associated with reduced fertility and decreased efficacy of assisted reproductive treatments 1
- Incidental findings - many polyps are discovered during imaging for other indications
Diagnostic Characteristics on Imaging
On sonohysterography, endometrial polyps demonstrate specific features that differentiate them from submucosal leiomyomas with 97% accuracy 4:
Polyp-specific features:
- Intact myometrial-endometrial interface
- Single feeding vessel
- Acute angle with the endometrium
- Homogeneous echogenicity
Doppler ultrasound can identify vessels within polyps, though it cannot reliably distinguish benign polyps from malignant lesions 4.
Important Clinical Caveat
Despite excellent imaging capabilities, sonohysterography and other imaging modalities cannot distinguish benign endometrial polyps from endometrial cancer with sufficient certainty 4. Therefore, endometrial sampling or direct visualization with hysteroscopy is mandatory in women with suspected endometrial pathology to exclude malignancy 4.
Underlying Pathophysiology
Recent genomic studies reveal that 74% of endometrial polyps harbor chromosomal rearrangements affecting HMGA1 and HMGA2 genes 5, indicating these are clonal proliferations with specific genetic drivers rather than simple reactive hyperplasia. Additional contributing factors include:
- Hormonal imbalances
- Chronic inflammation
- Metabolic factors (obesity, metabolic syndrome)
- Altered endometrial microbiota 6