Journal of the European Society for Gynaecological Endoscopy


Junctional zone thickening: an endo-myometrial unit disorder

S. Gordts1,4, G. Grimbizis2, V. Tanos3, P. Koninckx4, R. Campo5,1

1 Leuven Institute for Fertility & Embryology, Schipvaartstraat 4, 3000 Leuven, Belgium
2 Aristotle University of Thessaloniki, 1st Dept Obstetrics and Gynaecology, Tsimiski 51 Street, 54623 Thessaloniki, Greece
3 University of Nicosia, Aretaeio Hospital, Dep Obstetrics & Gynaecology, Nicosia, Cyprus
4 Latifa Hospital, Dubai, United Arab Emirates, Prof. em. ObGyn KULeuven, Belgium
5 Life Expert Centre, Schipvaartstraat 4, 3000 Leuven, Belgium


Adenomyosis, junctional zone, infertility, reproduction

Published online: Dec 13 2023


Adenomyosis is a disease defined by histopathology, mostly of hysterectomy specimens, and classification is challenged by the disagreement of the histologic definition. With the introduction of Magnetic Resonance Imaging (MRI) and two- and three-dimensional ultrasound, the diagnosis of adenomyosis became a clinical entity. In MRI and US, adenomyosis ranges from thickening of the inner myometrium or junctional zone to nodular, cystic, or diffuse lesions involving the entire uterine wall, up to a well-circumscribed adenomyoma or a polypoid adenomyoma. The absence of an accepted classification and the vague and inconsistent terminology hamper basic and clinical research. The sub-endometrial halo seen at US and MRI is a distinct entity, differing from the outer myometrium by its increased nuclear density and vascular structure. The endometrium and the sub-endometrial muscularis or archimetra are of Müllarian origin, while the outer myometrium is non-Mullerian mesenchymal. The junctional zone (JZ) is important for uterine contractions, conception, implantation, and placentation. Thickening of the JZ can be considered inner myometrium adenomyosis, with or without endometrial invasion. Changes in the JZ should be considered a different entity than myometrial clinically associated with impaired conception, implantation, abnormal uterine bleeding, pelvic pain and obstetrical outcome. Pathology of the basal endometrium and JZ is a separate entity and should be identified as an endo-myometrial unit disorder (EMUD).