Uterine Fibroids Characteristics and Clinical Implications

Benign Nature and Prevalence

Uterine fibroids represent benign sex steroid-responsive clonal expansions of individual smooth uterine muscle cells, with histology virtually indistinguishable from normal myometrium 1
Fibroids 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 should undergo careful pathologic examination 1

Fibroids occur in 20-50% of women over the age of 30 years, with prevalence increasing with age 3
By age 50, the estimated incidence exceeds 80% in Black women and approaches 70% in White women 2
Transvaginal ultrasound provides high sensitivity (90-99%) and specificity (98%) for detecting fibroids 4

Fibroids, especially the submucosal type, are associated with increased risks of reproductive complications including spontaneous abortion, preterm delivery, and postpartum hemorrhage 6
The effect of fibroids on fertility remains somewhat controversial, though impaired gamete transport, distortion of the endometrial cavity, and impaired blood supply to the endometrium may reduce implantation rates 6
Postmenopausal status with fibroid growth or persistent abnormal uterine bleeding significantly increases suspicion for malignancy 4
Leiomyosarcomas comprise only 0.1% of all uterine tumors, but the incidence increases to 1.7% in women undergoing hysterectomy for fibroids in their seventh decade of life 1