Uterine Polyps for USMLE Step 2
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Uterine Polyps for the USMLE Step 2 Exam
Definition and Pathophysiology
- Definition
- Uterine polyps are benign overgrowths of endometrial tissue that project into the uterine cavity. These growths are composed of endometrial glands, stroma, and blood vessels.
- Polyps can be single or multiple and vary in size from a few millimeters to several centimeters. They may 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 proliferation.
- Genetic mutations, such as in PTEN and beta-catenin pathways, may play a role in their development, leading to excessive cellular growth.
Risk Factors
- Age: Polyps are more common in perimenopausal and postmenopausal women, typically between ages 40-50.
- Estrogen Exposure: Unopposed estrogen or tamoxifen use (a selective estrogen receptor modulator) increases the risk due to its partial agonist effect on endometrial tissue.
- Obesity: Excess adipose tissue leads to peripheral conversion of androgens to estrogen, raising the risk.
- Hypertension: Some studies suggest a link between hypertension and endometrial polyp formation.
Clinical Manifestations
- Abnormal Uterine Bleeding (AUB):
- The most common symptom, presenting as intermenstrual bleeding, menorrhagia (heavy menstrual bleeding), or postmenopausal bleeding.
- Bleeding is particularly common in perimenopausal women.
- Infertility:
- Polyps may impair fertility by obstructing sperm pathways, affecting embryo implantation, or reducing uterine receptivity.
- Polypectomy (surgical removal) has been shown to improve conception rates in women with infertility.
- Asymptomatic:
- Many polyps are incidentally found during routine imaging or evaluations for other complaints.
Diagnosis
- Clinical Evaluation:
- History of abnormal bleeding patterns or infertility may indicate the presence of polyps.
- Physical exam is typically unremarkable unless polyps are large or prolapsed through the cervix.
- Imaging:
- Transvaginal Ultrasound (TVUS): First-line imaging tool that reveals polyps as focal endometrial thickenings or masses within the uterine cavity.
- Saline Infusion Sonohysterography (SIS): Saline infusion into the uterine cavity during ultrasound enhances visualization, especially for smaller polyps.
- Hysteroscopy:
- Gold standard for diagnosis, allowing direct visualization and biopsy.
- Enables concurrent polypectomy for symptomatic or suspicious polyps.
Differential Diagnosis
- Leiomyomas (Fibroids): Uterine smooth muscle tumors that also cause abnormal bleeding, often differentiated by ultrasound.
- Endometrial Hyperplasia: Diffuse endometrial thickening, which can appear similar to polyps but may show a more generalized pattern.
- Endometrial Cancer: Must be ruled out in postmenopausal women with abnormal bleeding; biopsy is often required.
Management
- Observation:
- Small, asymptomatic polyps in premenopausal women may be monitored, as they can regress spontaneously.
- Medical Management:
- Hormonal Therapy: Oral contraceptives or progestins may help manage associated bleeding but do not eliminate polyps.
- Limited effectiveness for definitive treatment, often reserved for bleeding control.
- Surgical Treatment:
- Hysteroscopic Polypectomy: Recommended for symptomatic polyps, large polyps, or in cases of infertility. Allows complete removal with minimal risk and is effective for symptom relief.
- Polypectomy in Postmenopausal Women: Highly recommended due to the small but increased risk of malignancy.
Key Points
- Uterine Polyps are benign endometrial overgrowths that project into the uterine cavity, commonly causing abnormal uterine bleeding and infertility.
- Pathophysiology involves estrogen-dependent hyperplasia of endometrial glands, often with underlying genetic alterations.
- Risk Factors: Perimenopausal age, obesity, unopposed estrogen or tamoxifen therapy, and hypertension.
- Symptoms: Abnormal uterine bleeding (intermenstrual, menorrhagia, postmenopausal) and, less commonly, infertility. Many polyps are asymptomatic.
- Diagnosis: Typically involves transvaginal ultrasound, with saline infusion sonohysterography enhancing visualization. Hysteroscopy is the gold standard for confirmation and treatment.
- Management:
- Observation for small, asymptomatic polyps in premenopausal women.
- Hysteroscopic Polypectomy for symptomatic, large, or suspicious polyps, especially in postmenopausal women.
- Complications: Although rare, malignancy can occur, particularly in postmenopausal women, making removal and histopathologic examination essential in these cases.