What are uterine fibroids, their types, symptoms, diagnosis, management options, and potential complications, including degeneration and less common types like cervical and broad ligament fibroids?

Comprehensive Overview of Uterine Fibroids

Definition and Pathophysiology

Uterine fibroids (leiomyomas or myomas) are benign clonal neoplasms arising from smooth muscle cells and fibroblasts of the myometrium, embedded in an extracellular matrix of collagen, fibronectin, and proteoglycan. 1, 2

• These represent sex steroid-responsive clonal expansions of individual smooth uterine muscle cells, with histology virtually indistinguishable from normal myometrium 2
• They are the most common benign tumors of the female genital tract and likely the most common soft-tissue tumors in the entire body 2
• For practical purposes, these tumors should be considered benign in premenopausal women, though all specimens require careful pathologic examination 2

Classification by Location

Standard Anatomical Types

• Submucosal (SM) fibroids: Project into the uterine cavity and are most strongly associated with abnormal uterine bleeding and reproductive complications 3
• Intramural (IM) fibroids: Located within the myometrial wall without cavity distortion 3
• Subserosal (SS) fibroids: Project outward from the uterine serosa 3
• Pedunculated fibroids: Attached to the uterus by a stalk, can be either submucosal or subserosal 3

Less Common Anatomical Variants

• Cervical fibroids: Located in the cervix and may not respond as well or have a durable response to embolization 3
• Broad ligament fibroids: Extend laterally into the broad ligament; MRI is superior for identifying these variants and may alter management in up to 28% of patients 3
• Intracavitary fibroids: Completely within the uterine cavity, amenable to hysteroscopic resection 3

Types of Fibroid Degeneration

Hyaline Degeneration

• The most common type of degeneration occurring in fibroids 4
• Results from inadequate blood supply as fibroids outgrow their vascular supply 4

Red (Carneous) Degeneration

• Presents with severe sudden-onset pain, fever, nausea, and leukocytosis requiring supportive care with NSAIDs and observation 1
• Most commonly occurs during pregnancy due to rapid growth and vascular compromise 4

Cystic Degeneration

• Occurs when hyaline degeneration progresses to liquefaction 4
• Can be identified on imaging studies 4

Calcific Degeneration

• More common in postmenopausal women 4
• CT can better delineate calcified fibroids relative to US and MRI, which may have treatment implications 3

Necrobiotic Degeneration

• Results from complete vascular occlusion 4
• Can occur spontaneously or following interventional procedures like uterine artery embolization 4

Malignant Transformation (Leiomyosarcoma)

• Extremely rare, comprising only 0.1% of all uterine tumors, but incidence increases to 1.7% in women undergoing hysterectomy for fibroids in their seventh decade of life 2
• Rapid growth of fibroids can occasionally indicate malignant transformation and should prompt urgent referral 1
• Postmenopausal status with fibroid growth or persistent abnormal uterine bleeding significantly increases suspicion for malignancy 2

Epidemiology and Risk Factors

• Fibroids occur in 20-50% of women over age 30, with prevalence increasing with age 3, 2
• By age 50, the estimated incidence exceeds 80% in Black women and approaches 70% in White women 1, 2
• Black women develop clinically significant disease at an earlier age and experience racial disparities, including higher rates of surgical intervention and lower rates of minimally invasive approaches 1
• Risk factors include age, nulliparity, race, family history, obesity, and body mass index 1

Clinical Presentation and Symptoms

Bleeding Symptoms

• Menorrhagia is the most frequent symptom, often resulting in iron deficiency anemia 1
• May present as prolonged menstrual bleeding or intermenstrual bleeding 1

Bulk Symptoms

• Pelvic pain and pressure 3, 1
• Urinary urgency and frequency 1
• Constipation 1
• Dysmenorrhea 1
• Low back pain 5
• Dyspareunia 5

Reproductive Complications

• Submucosal fibroids are associated with increased risks of spontaneous abortion, preterm delivery, abnormal presentation in labor, pelvic outlet obstruction, postpartum hemorrhage, and puerperal sepsis 3, 2
• Potential impairment of fertility through impaired gamete transport, distortion of the endometrial cavity, impairment of blood supply to the endometrium, and atrophy and ulceration 3, 2

Diagnostic Approach

Physical Examination

• Perform abdominal examination, speculum examination, and bimanual pelvic evaluation to characterize the location, shape, and mobility of fibroids 3, 1

Imaging Modalities

Ultrasound (First-Line)

• Transvaginal ultrasound provides high sensitivity (90-99%) and specificity (98%) for detecting fibroids 2
• Combination of transabdominal and transvaginal ultrasound is frequently used in pretreatment evaluation 3
• Transabdominal ultrasound is useful for significantly enlarged fibroid uterus or large subserosal/pedunculated fibroids 3
• Color Doppler shows increased peripheral vascular flow in fibroids 3
• The "bridging vessel sign" (interface vessels between uterus and juxtauterine masses) differentiates subserosal fibroid from extrauterine tumors 3
• Resistive index <0.7 and pulsatility index <1.2 on spectral Doppler showed 93.4% sensitivity and 95.6% specificity in differentiating leiomyoma from adenomyosis 3

MRI (Superior for Complex Cases)

• MRI is superior to ultrasound for identifying and mapping fibroids and may alter management in up to 28% of patients 3
• When MRI is clinically useful, gadolinium-based IV contrast is preferred 3
• Provides information on fibroid location, volume, number, T1- and T2-weighted signal intensity, and enhancement 3
• Postcontrast imaging allows assessment of fibroid viability, uterine artery anatomy, and detection of ovarian arterial collateral supply 3
• Nonviable/autoinfarcted fibroids are found in up to 20% of UFE candidates and do not respond to UFE 3
• Diffusion-weighted imaging with ADC can help distinguish fibroids from sarcomas, achieving 98% sensitivity and 96% specificity when incorporated into an MRI algorithm 3

CT

• Not recommended for initial imaging but can better delineate calcified fibroids 3

Additional Workup

• Pregnancy testing 3
• Hemoglobin levels to assess for anemia 3
• Endometrial biopsy if features raise concern for other causes of heavy menstrual bleeding 3

Management Options

Expectant Management

• Recommended for asymptomatic patients because most fibroids decrease in size during menopause 5
• Advisable to follow-up patients to document stability in size and growth 6

Medical Management

For Heavy Menstrual Bleeding

• Hormonal contraceptives (combined oral contraceptives) 7, 6, 5
• Tranexamic acid 5
• Nonsteroidal anti-inflammatory drugs 5
• Progestogens 7

For Preoperative Symptom Relief or Approaching Menopause

• Gonadotropin-releasing hormone (GnRH) agonists are among the most effective medical therapies with the most evidence to support fibroid volume reduction and symptomatic improvement in menstrual bleeding 6, 5
• Selective progesterone receptor modulators (SPRMs) are the most effective medical therapies and can be administered intermittently long-term with good results on bleeding and fibroid size reduction 7, 6

Surgical Management

Fertility-Preserving Options

Hysteroscopic Myomectomy

• Involves transvaginal, transcervical placement of hysteroscope and removal of submucosal fibroids 3
• Indicated for patients with submucosal fibroids desiring uterus preservation 3
• Intracavitary fibroids are amenable to hysteroscopic resection 3

Abdominal/Laparoscopic Myomectomy

• Pregnancy rates of 54-59.5% reported after myomectomy in patients with no other infertility factors 3
• Submucosal, intramural, and broad-based subserosal fibroids are amenable to surgical myomectomy 3

Definitive Treatment

Hysterectomy

• Accounts for one-third to half of all fibroid treatments 4
• Infertility is permanent and irreversible following hysterectomy 3
• Approximately three-quarters of all fibroid treatments are hysterectomies 4

Minimally Invasive Interventional Procedures

Uterine Artery Embolization (UAE/UFE)

• Well-recognized as a uterine-sparing (fertility-preserving) method 8
• Submucosal and intramural fibroids that contact the endometrium may be expelled following successful UFE in 2.2% to 7.7% of cases 3
• Cervical fibroids may not respond as well or have a durable response to embolization 3
• Pedunculated fibroids may be treated with UFE depending on location and stalk caliber 3

MR-Guided Focused Ultrasound Surgery (MRgFUS)

• Minimal access treatment option using ultrasound waves for fibroid ablation 8

Radiofrequency Ablation

• VizAblate™ and Acessa™ systems available for uterine fibroid ablation 8

Endometrial Ablation

• Associated with high risk of pregnancy complications 3
• No relevant literature supports use in patients desiring to preserve fertility 3

Treatment Selection Algorithm

The choice of treatment depends on:

1. Patient's age and fertility desires 7, 5
2. Number, size, and location of fibroids 3, 7
3. Presence and severity of symptoms 7, 6
4. Access to treatment and physician experience 5

For asymptomatic patients: Expectant management with follow-up 6, 5

For symptomatic patients desiring fertility:

• Submucosal fibroids → Hysteroscopic myomectomy 3
• Intramural/subserosal fibroids → Laparoscopic/abdominal myomectomy or UFE 3
• Medical therapy for symptom control or preoperative preparation 6, 5

For symptomatic patients not desiring fertility:

• Medical management for bleeding control 6, 5
• Minimally invasive procedures (UFE, MRgFUS, radiofrequency ablation) 8
• Hysterectomy for definitive treatment 4

Economic Impact

• Total estimated societal costs range from $5.9 to $34.4 billion annually, with lost work hours accounting for the largest proportion 1

Critical Pitfalls and Red Flags

• Suspect malignant transformation if rapid growth occurs, especially in postmenopausal women not on hormone replacement therapy 1, 2
• Conventional MRI cannot accurately differentiate fibroids from sarcomas; diffusion-weighted imaging with ADC is needed 3
• Nonviable/autoinfarcted fibroids (found in up to 20% of UFE candidates) do not respond to UFE and must be identified during treatment planning 3
• Cervical and broad ligament fibroids may require different treatment approaches than standard fibroids 3