Uterine Polyps for USMLE Step 1
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Uterine Polyps for the USMLE Step 1 Exam
Definition and Pathophysiology
- Definition
- Uterine polyps are benign endometrial overgrowths that extend into the uterine cavity. These growths are composed of glands, stroma, and blood vessels.
- Polyps vary in size and can be either pedunculated (on a stalk) or sessile (flat-based).
- Pathophysiology
- Arise from localized hyperplasia of endometrial glands and stroma.
- Influenced by estrogen, which stimulates endometrial cell proliferation.
- Genetic mutations, such as in PTEN and beta-catenin pathways, may increase cellular proliferation risk, contributing to polyp formation.
Risk Factors
- Age: More common in women approaching menopause (40-50 years).
- Hormonal Factors: Linked to estrogen exposure, including unopposed estrogen therapy.
- Tamoxifen Use: Tamoxifen, a selective estrogen receptor modulator used in breast cancer treatment, increases polyp risk due to its partial agonist effect on uterine tissue.
- Obesity: Increased peripheral conversion of androgens to estrogen in adipose tissue elevates estrogen levels.
Clinical Manifestations
- Abnormal Uterine Bleeding (AUB):
- Common presentations include intermenstrual spotting, heavy menstrual bleeding (menorrhagia), or postmenopausal bleeding.
- Irregular bleeding is frequently observed in perimenopausal women with polyps.
- Infertility:
- Polyps can interfere with embryo implantation or disrupt uterine receptivity, contributing to infertility.
- Asymptomatic: Many polyps are found incidentally on imaging or evaluation for unrelated symptoms.
Diagnosis
- Clinical History and Physical Exam:
- Abnormal bleeding patterns or infertility should raise suspicion.
- Physical examination typically reveals no abnormal findings unless large polyps are prolapsed through the cervix.
- Imaging:
- Transvaginal Ultrasound (TVUS): The first-line imaging technique for visualizing polyps, where they appear as focal endometrial thickenings or hyperechoic masses.
- Saline Infusion Sonohysterography (SIS): Saline infusion during ultrasound enhances visualization, especially for smaller polyps.
- Hysteroscopy:
- The gold standard for diagnosis, allowing direct visualization and biopsy.
- Enables simultaneous removal of polyps, especially if symptomatic or suspected of malignancy.
Differential Diagnosis
- Endometrial Hyperplasia: Generalized thickening of the endometrium, often associated with unopposed estrogen exposure.
- Leiomyomas (Fibroids): Benign smooth muscle tumors of the uterus that can present similarly but have a distinct ultrasound appearance with shadowing and different echotexture.
- Endometrial Cancer: Must be ruled out, particularly in postmenopausal women with bleeding.
Management
- Observation:
- Asymptomatic polyps, particularly in premenopausal women, may not require immediate intervention and can be monitored.
- Small polyps may regress spontaneously.
- Medical Therapy:
- Progestins: Can help control abnormal bleeding, though they do not eliminate polyps.
- Hormonal Therapy: Combined oral contraceptives (COCs) or other hormone therapies may help manage associated bleeding.
- Surgical Management:
- Hysteroscopic Polypectomy: The primary treatment for symptomatic polyps or polyps in patients with infertility or postmenopausal bleeding.
- Removal is also advised for larger polyps or those with atypical features due to a small but present risk of malignancy.
Key Points
- Uterine Polyps are benign growths of endometrial tissue that extend into the uterine cavity, often associated with abnormal uterine bleeding and infertility.
- Pathophysiology involves estrogen-driven hyperplasia and, in some cases, genetic mutations.
- Risk Factors: Advanced age, obesity, tamoxifen use, and high estrogen exposure.
- Symptoms: The most common symptom is abnormal uterine bleeding, including intermenstrual spotting and postmenopausal bleeding. Polyps may also contribute to infertility or be asymptomatic.
- Diagnosis relies on transvaginal ultrasound and saline infusion sonohysterography for enhanced visualization. Hysteroscopy is the gold standard for diagnosis and enables treatment.
- Management:
- Observation is possible for asymptomatic, small polyps.
- Hysteroscopic removal is recommended for symptomatic, large, or atypical polyps.
- Complications: Although rare, malignant transformation can occur, especially in postmenopausal women, necessitating removal and histopathologic examination in symptomatic or suspicious cases.