Objective: To compare ultrastructural features of leiomyoma cells from the same uterine myoma nodule before and after GnRH agonist (GnRH-a) treatment and to examine the relation between these ultrastructural changes and the extent of myoma volume reduction with GnRH-a treatment.
Design: Prospective clinical study.
Setting: University teaching hospital.
Patient(s): Twenty women with uterine leiomyomas who were scheduled for surgery.
Intervention(s): Transcervical needle biopsy of uterine myoma, s.c. leuprolide acetate injection (3.75 mg) at least three times every 4 weeks before surgery, and hysterectomy or myomectomy.
Main outcome measure(s): The changes in ultrastructural features of uterine leiomyoma cells and the percentage decrease in the volume of the largest myoma at 12 weeks of GnRH-a treatment measured by magnetic resonance imaging.
Result(s): A decrease in myofilaments, mitochondrial swelling, and emergence of the lysosomal body were observed in relation to GnRH-a treatment. Furthermore, a positive correlation was observed between the decrease in myofilaments and myoma shrinkage.
Conclusion(s): Cellular atrophy due to a decrease in myofilaments plays a major role in the reversible myoma shrinkage resulting from GnRH-a treatment.