Uterine Fibroids (Leiomyoma)
Benign smooth-muscle tumors of the myometrium causing heavy bleeding, bulk symptoms, and reproductive complications.
Also known as: fibroids, leiomyoma, myoma, uterine myoma
Overview
Benign monoclonal smooth-muscle tumors arising from the myometrium, classified by location (FIGO 0-8): submucosal (0-2), intramural (3-5), subserosal (6-7), or other (8, e.g., cervical, parasitic).
Epidemiology
Most common pelvic tumor in women; cumulative incidence by age 50 is ~70% in white women and >80% in Black women. Black women develop fibroids earlier, more numerous, larger, and more symptomatic.
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Risk factors
- Black race (2-3x relative risk)
- Early menarche, nulliparity
- Obesity, hypertension
- Family history
- Vitamin D deficiency
Pathophysiology
Estrogen- and progesterone-responsive tumors arising from a single myometrial smooth-muscle progenitor; MED12 mutations identified in ~70%. Grow during reproductive years and typically regress after menopause. Heavy bleeding results from distorted endometrial vasculature and impaired hemostasis; bulk symptoms from mass effect.
Clinical presentation
Symptoms
- Heavy menstrual bleeding (most common); prolonged or intermenstrual bleeding
- Pelvic pressure or fullness, bloating, increased abdominal girth
- Urinary frequency or hesitancy (anterior fibroids on bladder)
- Constipation or tenesmus (posterior fibroids on rectum)
- Dysmenorrhea, dyspareunia
- Infertility, recurrent pregnancy loss (especially submucosal)
- Many fibroids are asymptomatic and found incidentally
Signs / physical exam
- Enlarged, irregular, firm, nontender uterus on bimanual exam
- Uterine size often described in 'weeks' as in pregnancy
- Pallor or signs of anemia in chronic blood loss
Classic findings
Premenopausal woman with heavy menses, iron-deficiency anemia, and an enlarged irregular uterus.
Differential diagnosis
- Adenomyosis — Diffusely enlarged, tender, boggy uterus; heavy painful menses; MRI shows widened junctional zone
- Endometrial polyp — Intermenstrual bleeding; saline-infusion sonohysterography or hysteroscopy
- Endometrial hyperplasia/cancer — Postmenopausal or atypical bleeding; endometrial biopsy mandatory if risk factors
- Leiomyosarcoma — Rapid growth (especially postmenopausal), heterogeneous on MRI; rare (<1% of myomectomy specimens)
- Ovarian mass — Adnexal location, may be confused with pedunculated subserosal fibroid; MRI clarifies
- Pregnancy (intrauterine or ectopic) — Always check hCG with abnormal bleeding or uterine enlargement
- Adenocarcinoma of cervix or uterus — Postmenopausal bleeding, abnormal Pap; biopsy
Diagnostic workup
Labs
- CBC (iron-deficiency anemia common), ferritin
- TSH, prolactin if irregular bleeding
- Pregnancy test
- Endometrial biopsy if age ≥45, risk factors for hyperplasia, or persistent abnormal bleeding
Imaging
- Transvaginal ultrasound — first-line; characterizes size, number, location
- Saline-infusion sonohysterography or hysteroscopy — best for submucosal fibroids and cavity distortion
- MRI — pre-operative mapping, suspected adenomyosis, or assessment before uterine artery embolization
Diagnostic algorithm
| FIGO Type | Location | Best Approach |
|---|---|---|
| 0 | Pedunculated submucosal, entirely in cavity | Hysteroscopic resection |
| 1 | Submucosal, <50% intramural | Hysteroscopic resection |
| 2 | Submucosal, ≥50% intramural | Hysteroscopic (skilled) or laparoscopic |
| 3 | 100% intramural, contacts endometrium | Myomectomy (laparoscopic/abdominal) |
| 4 | Intramural, no cavity or serosa contact | Myomectomy if symptomatic |
| 5-7 | Subserosal | Laparoscopic myomectomy |
| 8 | Other (cervical, parasitic) | Individualized |
Treatment
First-line
- Expectant management for asymptomatic fibroids
- NSAIDs for dysmenorrhea
- Tranexamic acid 1.3 g TID × up to 5 days per cycle for heavy bleeding
- Combined hormonal contraception or progestin-only options for bleeding control
- Levonorgestrel IUD — effective for heavy menstrual bleeding when cavity not significantly distorted
- Iron supplementation for anemia
Procedural / surgical
- Hysteroscopic myomectomy — submucosal fibroids (FIGO 0-2)
- Laparoscopic, robotic, or abdominal myomectomy — preserves fertility
- Uterine artery embolization — alternative for women not pursuing pregnancy (data on subsequent fertility limited)
- MR-guided focused ultrasound (MRgFUS) — selected cases
- Hysterectomy — definitive; vaginal, laparoscopic, or abdominal route based on size
Second-line / adjunct
- GnRH agonist — leuprolide, goserelin — short-term (3-6 months) preoperative shrinkage; add-back therapy if used longer
- GnRH antagonist with add-back — elagolix/estradiol/norethindrone, relugolix/estradiol/norethindrone — approved for heavy menstrual bleeding due to fibroids
- Selective progesterone receptor modulators (where available; ulipristal — restricted in many regions due to hepatotoxicity)
Complications
- Iron-deficiency anemia from chronic heavy bleeding
- Infertility, recurrent pregnancy loss (submucosal especially)
- Pregnancy complications: malpresentation, obstructed labor, postpartum hemorrhage, red degeneration (painful infarction in pregnancy)
- Hydronephrosis from ureteral compression by large fibroids
- Rare leiomyosarcoma (<1% — historically overestimated)
PANCE pearls
- Submucosal fibroids (FIGO 0-2) most disrupt fertility and bleeding; hysteroscopic myomectomy can dramatically improve both.
- Avoid morcellation in women at risk for occult malignancy (postmenopausal, rapid growth) due to risk of disseminating leiomyosarcoma.
- Tranexamic acid is highly effective for heavy menstrual bleeding and is contraindicated in patients with active thromboembolic disease.
- Red degeneration in pregnancy presents with localized pain, low-grade fever, and leukocytosis — manage conservatively with analgesics.
- Fibroids regress after menopause; postmenopausal growth raises concern for sarcoma.
References
- ACOG PB 228 — ACOG Practice Bulletin No. 228: Management of Symptomatic Uterine Leiomyomas (Obstet Gynecol 2021)
- FIGO Classification — FIGO Classification System (PALM-COEIN) for Causes of Abnormal Uterine Bleeding (Munro et al., Int J Gynaecol Obstet 2011)
- AAGL 2012 — AAGL Practice Report: Diagnosis and Management of Submucous Leiomyomas (J Minim Invasive Gynecol 2012)
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