The challenge of FIGO type 3 leiomyomas and infertility: Exploring therapeutic alternatives amidst limited scientific certainties

Abstract

Uterine leiomyomas (ULs) are non-cancerous tumors composed of smooth muscle cells that develop within the myometrium and represent the most prevalent pathological condition affecting the female genital tract. Despite the volume of available research, many aspects of ULs remain unresolved, making it a "paradoxical disease" where the increase in available scientific literature has not been matched by an increase in solid evidence for clinical management. Fertility stands at the top of the list of clinical issues where the role of ULs is still unclear. The leiomyoma subclassification system, released by the International Federaion of Gynecology and Obstetrics (FIGO) in 2008, introduced a new and more effective way of categorizing uterine fibroids. The aim was to go beyond the traditional classification "subserosal, intramural and submucosal", facilitating a detailed examination of individual ULs impact on the female reproductive system. The "type 3 UL" is a special type of myoma, characterized by its complete myometrial development while encroaching the endometrium. It is a unique "hybrid" between a submucous and an intramural UL, that may exert a detrimental "double hit" mechanism, which is of particular interest in patients wishing pregnancy. To date, no robust evidence is available regarding the management of type 3 ULs. The aim of this narrative review is to provide a comprehensive overview of the physiopathological mechanisms that type 3 UL may exert on fertility, and to present new perspectives that may help us to better understand both the need for and the methods of treating this unique type of fibroid.