Morphometric and electron-microscopic analyses of the effects of gonadotropin-releasing hormone agonists on uterine leiomyomas.

OBJECTIVE: Reports on the histologic effects of gonadotropin-releasing hormone agonists on uterine leiomyomas provide conflicting results. Most previous studies used qualitative methods of analysis. Using quantitative and semiquantitative stereologic methods of analysis, we assessed volume density of hyalinized areas, cell density, nuclear volume, and cytoplasmic cross-sectional areas of smooth muscle cells in histologic sections and also measured diameters of collagen fibrils in electron micrographs of uterine leiomyomas.
DESIGN: Thirty leiomyomas from patients treated with gonadotropin-releasing hormone agonists (10 different patient samples), age-matched control patients (10 different patient samples), and postmenopausal women (10 different patient samples) were used. Hyalinization was assessed using a microscope with a projection head and affixed morphometric grid. Cell size and density were evaluated using a video-based, computerized system attached to the microscope, for which morphometric ad hoc programs were written. Diameters of collagen fibrils were measured from electron micrographs.
SETTING: The study was conducted in the Department of Pathology, Mount Sinai Medical Center, New York, NY. PATIENTS: A total of 30 patient samples were studied, with three groups comprising 10 samples each, including patients treated with gonadotropin-releasing hormone agonists, age-matched control patients, and postmenopausal women.
RESULTS: Myomas from patients treated with gonadotropin-releasing hormone agonists exhibited more hyalinization, greater cell density, slightly smaller cell sizes, and larger collagen fibrils than those of age-matched control patients and postmenopausal women.
CONCLUSIONS: Shrinkage after treatment with gonadotropin-releasing hormone agonists is attributed to smaller cell size and increased collagenization in myomas.