Adenomyosis, a menstruation-related uterine disorder, refers to the presence of endometrial stroma and glands within the myometrium and is typically observed in reproductive-age women. The pathogenesis explaining the migration, persistence, proliferation and differentiation of ectopic endometrial cells includes a genetic and epigenetic background, an oestrogen/progesterone receptor imbalance and an inflammatory reaction driven by local immune dysfunction, along with fibrosis and neuroangiogenesis within the myometrium. In the past, it was thought that adenomyosis almost exclusively affected multiparous women after 40 years of age and the diagnosis was generally confirmed upon hysterectomy. Nowadays, using imaging techniques such as transvaginal ultrasonography and magnetic resonance imaging, adenomyosis is increasingly identified in young women with dysmenorrhoea, dyspareunia, abnormal uterine bleeding and heavy menstrual bleeding, and also in infertile patients. Furthermore, adenomyosis often coexists with other gynaecological conditions, such as endometriosis and uterine fibroids. Despite the improvement of non-invasive diagnostic tools, the awareness of the condition is still poor and the diagnosis is often missed, due also to a heterogeneity in clinical presentation and imaging criteria. In addition, medical and surgical management do not follow shared recommendations, even though adenomyosis requires a lifelong management plan, including pain and bleeding control, fertility preservation and pregnancy complications.