Uterine Fibroids

General Considerations

• Uterine fibroids are leiomyomas, benign tumors of smooth muscle origin
• Occur in between 20-50% of women > 30 years of age
• Fibroids may enlarge with elevated estrogen levels
  • They enlarge during the first trimester of pregnancy
• Uterine fibroids diminish in size after menopause
• More common in blacks than whites (3:1)
• Most are intramural, i.e. middle of myometrium
• Most fibroids are in the fundus and body of the uterus
  • Others can be subserosal or exophytic, or
  • Submucosal and subendometrial (rarely) 

Clinical Findings

• Most women are asymptomatic
• Symptoms can include
  • Menorrhagia (increased duration or flow)
    • Frequently from a submucosal fibroid
• Pain
• Urinary frequency, urgency or incontinence
• Infertility 

Imaging Findings

• Ultrasound is the study of choice
• Conventional radiography
  • Soft tissue mass arising from the pelvis but separate from the urinary bladder
• Amorphous, flocculent calcifications in the pelvis
  • May resemble “popcorn” or may calcify the outer rim of fibroid
• Displacement of bowel gas up and out of the pelvis
• Ultrasound
• Echogenic mass if fibrosis prevails
• Hypoechoic, solid mass if muscle component is prevalent
• Sharp discrete shadows
• Anechoic features if central portion of fibroid has degenerated
• MRI
• Low/intermediate signal intensity of T1 and T2 weighted images
• High central signal intensity on T2 from hemorrhage
• May have hyperintense rim
• With contrast, most are hypointense, about 25% isointense and 10% hyperintense to myometrium
• CT
• Mass containing mixed densities, low attenuation if necrotic and higher attenuation if calcified or hemorrhagic 

Differential Diagnosis

• Ovarian neoplasm or cyst
• Dilated urinary bladder
• Intrauterine pregnancy
• Hydatidiform mole 

Treatment

• Surgery or arterial embolization for pain and menorrhagia 

Complications

• Rarely (< 1%), malignant degeneration to a leiomyosarcoma
• Exophytic fibroid can torse and cause pain
• Infertility from interference with implantation
• During pregnancy
  • Spontaneous abortion
• Intrauterine growth retardation
• Postpartum hemorrhage

Uterine Fibroids. Conventional radiograph on the left shows displacement of the bowel gas out of the pelvis because of a large soft tissue mass (white arrows) arising from the pelvis and extending into the lower abdomen. Contrast-enhanced coronal reformatted CT scan of the abdomen on right demonstrates a large pelvic mass comprised of degenerating fibroids (black arrow), hemorrhage (white arrow) and calcification (dotted white arrow).
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Uterine Fibroids. Conventional radiograph on the left shows a large soft tissue mass (black arrows) arising from the pelvis and extending into the lower abdomen. Non-contrast-enhanced coronal reformatted CT scan of the abdomen on right demonstrates a large pelvic mass comprised of a large fibroid (white arrow), with some areas of degeneration (red arrows).

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Williams Obstetrics 22^nd Ed McGraw Hill