The Hormonal Origin of Uterine Fibroids: An Hypothesis

Abstract

Uterine fibroids are the commonest of pelvic neoplasms and therefore should command the interest of all gynecologists. What is the source of these tumors is a question that is asked daily and one which can be answered only in generalities. In three former contributions (1, 2, 3) excessive stimulation of the myometrium by the ovarian follicular hormone has been suggested as a cause. That the action of this hormone is not specific for the endometrium, as demonstrated by the endometrial changes during the normal menstrual cycle, but that it affects the genital tract as a whole, is easily proved (4). When the action on the endometrium is abnormal, with resulting endometrial hyperplasia, there is an equally abnormal action upon the myometrium, which, if it is prolonged sufficiently, results in cellular metaplasia of the uterine muscle cell or cells, with the subsequent development of uterine fibroids. According to Meyer (5), the histogenetic study of fibroids does not reveal any distinctive myoma mother cells in the uterine muscle from which a proliferating myoma might develop. He reports that the earliest appearance of a myoma is represented by a thickening of the uterine muscle bundles which are directly connected with the normal musculature of the uterus. De Snoo (6), on the other hand, claims that the uterus is a very primitive special organ which contains many undifferentiated cells, genitoblasts. During embryonic life these cells form the uterus proper, while in later life they provide the means of gestational hyperplasia and of regeneration of the endometrium during the puerperium. Under pathological conditions, due to ovarian hormonal dysfunction, these genitoblasts can give rise to the formation of uterine fibroids, endometriomas, or adenomyomas.