Reproductive · Gynecology

Uterine Leiomyoma (Fibroids)

USMLE2PANCE
7

Bets

The facts most likely to be tested

1

Uterine leiomyomas are benign monoclonal tumors arising from the smooth muscle cells of the myometrium and are highly estrogen-dependent.

Confidence:
2

The most common clinical presentation is abnormal uterine bleeding (specifically menorrhagia) and a firm, irregularly enlarged, mobile uterus on bimanual exam.

Confidence:
3

Transvaginal ultrasound is the first-line imaging modality to confirm the diagnosis and characterize the size and location of the fibroids.

Confidence:
4

Submucosal fibroids are most strongly associated with infertility and recurrent pregnancy loss due to distortion of the endometrial cavity.

Confidence:
5

Gonadotropin-releasing hormone (GnRH) agonists (e.g., leuprolide) are used for preoperative shrinkage of fibroids but are limited by side effects mimicking menopause.

Confidence:
6

Hysteroscopic myomectomy is the treatment of choice for symptomatic submucosal fibroids in patients desiring future fertility.

Confidence:
7

Uterine artery embolization is a minimally invasive alternative for patients who wish to avoid surgery but is generally contraindicated in those desiring future pregnancy.

Confidence:

Vignette unlocked

A 34-year-old G0P0 woman presents with a 6-month history of heavy, prolonged menstrual bleeding and pelvic pressure. She reports that her periods have become increasingly painful and last 8 days. On physical examination, the abdomen is soft, and bimanual exam reveals a firm, irregularly enlarged, mobile uterus consistent with a 12-week gestation size. A transvaginal ultrasound demonstrates a 4 cm submucosal mass distorting the endometrial cavity. She is currently interested in preserving her fertility.

What is the most appropriate management for this patient?

+Reveal answer

Hysteroscopic myomectomy

The patient has symptomatic submucosal fibroids causing menorrhagia; hysteroscopic myomectomy is the gold standard for removing submucosal lesions while preserving fertility.

Mo

Depth

Full handout

High yield triage

Etiology / Epidemiology

Common benign smooth muscle tumors in reproductive-age women; highly dependent on estrogen and progesterone.

Clinical Manifestations

Presents with menorrhagia and a firm, irregular, mobile uterus on bimanual exam.

Diagnosis

Transvaginal ultrasound is the initial imaging of choice; MRI is the gold standard for mapping.

Treatment

Combined oral contraceptives are first-line for symptom control; hysterectomy is the definitive treatment.

Prognosis

Most are asymptomatic; infertility and recurrent pregnancy loss are significant complications.

Full handout

Epidemiology & Etiology

Most common pelvic tumor in women, with highest prevalence in African American populations. Growth is stimulated by estrogen and progesterone, explaining why they typically regress after menopause.

Pertinent Anatomy

Classified by location: submucosal (protruding into cavity), intramural (within wall), or subserosal (projecting outward). Submucosal fibroids are most likely to cause abnormal uterine bleeding.

Pathophysiology

Monoclonal tumors arising from uterine smooth muscle cells. Increased expression of estrogen receptors and local growth factors leads to excessive extracellular matrix deposition and cellular proliferation.

Clinical Manifestations

Patients often report menorrhagia leading to iron deficiency anemia. Physical exam reveals a firm, irregular, mobile uterus. Red flags include rapid growth, which raises suspicion for leiomyosarcoma.

Diagnosis

Transvaginal ultrasound is the initial diagnostic test. MRI is the gold standard for precise mapping of fibroid size and location, especially prior to surgical intervention.

Treatment

Symptomatic management begins with combined oral contraceptives or progestin-only methods. Leuprolide (a GnRH agonist) can shrink fibroids preoperatively. Contraindications for medical therapy include pregnancy and undiagnosed vaginal bleeding. Surgical options include myomectomy for fertility preservation or hysterectomy for definitive cure.

Prognosis

Fibroids are benign, but can cause infertility or obstetric complications like malpresentation. Serial ultrasounds are required if rapid growth is suspected to rule out malignancy.

Differential Diagnosis

Adenomyosis: presents with a uniformly enlarged, boggy uterus

Endometrial cancer: postmenopausal bleeding is the hallmark

Ovarian mass: usually adnexal rather than midline uterine

Pregnancy: always rule out with hCG

Leiomyosarcoma: suspected with rapid growth in postmenopausal women