title: "The Flemish Giant", reflections on the defense against endometriosis, inspired by Professor Emeritus Ivo A. Brosens.
abstract: Reproductive research benefits from combining animal and clinical studies. In Leuven, rabbits have constituted an animal model for many reproductive disorders, especially for those that involved surgical treatment. Much of what has been learned from animal experiments has been applied to human clinical reproductive research soon after. In this manuscript we wish to address the problem of the constant intra-abdominal battle between the menstrual aggressor and the peritoneal defense. From all published evidence we may conclude that endometriosis appears to be a dynamic disease, especially in the early phase, with subtle, atypical lesions emerging and vanishing again. In the end however the peritoneal defense system will prevail and the disease will be contained in the majority of patients. When doing repeat laparoscopies in young patients one should be prepared to encounter more advanced histological types of lesions, which not necessarily do have to indicate more advanced stages of the disease: the classical, blue and black powderburn spots and blueberry lesions reflect the extinguishing phase of the dynamic endometriotic process, and herald its inactivated histological end-stage. The dynamic phase of the disease may involve a varying interval of each patient's life, and medical suppression of the activity of the implants during this interval may lead one to conclude erroneously that treatment has been effective. If subsequently (after the end of medical suppression of the activity of the lesions) ovarian activity resumes and the lesions are stimulated again by ovarian steroids, their productive activity returns. Recurrence of disease may be diagnosed if at that stage a laparoscopy would be performed, whereas in reality only reactivation of temporarily obscured lesions did occur. The suppressed, dormant (but never absent) lesions produce mucus again, desquamation occurs, and reaction by the surrounding tissue. The inflammatory response, the local hyperemia and the neogenesis of vessels accentuate the presence of previously invisible endometriosis lesions and make them visible again. Endometriosis resumes its temporarily halted natural course of development, tissue remodeling occurs again, the battle between the aggressor and the defense resumes and waxing and waning of the several types of lesions, red, white and black, can be found again.
authors.affiliation: Academisch Ziekenhuis Maastricht and The University of Maastricht, Netherlands.
authors.forename: J L
authors.initials: JL
authors.lastname: Evers
authors.forename: J A
authors.initials: JA
authors.lastname: Land
authors.forename: G A
authors.initials: GA
authors.lastname: Dunselman
authors.forename: P J
authors.initials: PJ
authors.lastname: van der Linden
authors.forename: J C
authors.initials: JC
authors.lastname: Hamilton
mesh_terms: D000818:Animals; D004715:Endometriosis / Q000276:immunology / Q000503:physiopathology* / Q000628:therapy; D005260:Female; D006801:Humans; D008598:Menstruation; D010537:Peritoneum / Q000503:physiopathology; D011817:Rabbits