Histological pattern of leiomyomas after ulipristal acetate treatment in women: A case-control study

Purpose of Investigation: Assessing cytological and extracellular matrix histological patterns of uterine leiomyomas, in women previously treated with ulipristal acetate (UPA). Materials and Methods: Patients underwent surgical intervention for uterine leiomyomas between 2017 and 2018 were screened for previous use of UPA and were considered as cases. Controls were matched for race and non-menopausal status among patients with surgeries for leiomyomas. Fibrosis, hyalinosis, edema, necrosis, cellularity, phlogosis, and mitosis were assessed in the specimens of fibroids by a semiquantitative score. The rates of scores for each histological pattern were compared among cases and controls, and described in a two-dimensional correspondence analysis. Results: There is not significance among scores between cases and controls fibroids, except than for the hyalinosis of moderate grade, that seems more likely in the ulipristal acetate group. The fibroids after ulipristals appear to have less mitosis and cellularity, while it seems to have more hyalinosis, edema and, in case of two cycles of ulipristal, fibrosis. Conclusions: Histological changes of leiomyomas after UPA therapy are heterogeneous. UPA mostly acts on extracellular matrix and, to a lesser extent, on histological parameters of smooth muscle cell proliferation.