"Endometrial maldifferentiation" - A clinically significant diagnosis in equine reproduction?

Abstract

The present paper describes the functional morphology of endometrial maldifferentiation in mares according to the classification of Schoon et al. (1998). The primary diagnosis is based on the investigation of routinely H.-E. stained slides, supplemented by immunohistological techniques (estrogen and progesterone-receptors, Ki-67 antigen, intermediate filaments, laminin) of formalin-fixed biopsy specimens. The morphological findings are interpreted as indicative for hormonal disturbances due to ovarian neoplasms and various ovarian dystrophies, or as a symptom of alterations affecting either the hypothalamo-pituitary-ovarian-endometrial axis or the local steroid hormone receptor status. Clinical symptoms are mostly absent in cases without ovarian abnormalities. No relationship can be identified between endometrial maldifferentiation and the age or parity of the mare or season. From the authors' point of view endometrial maldifferentiation should be taken into account in the assessment of endometrial biopsy specimens as one important parameter leading to temporary or permanent fertility problems. In a certain case, however, the definite prognosis with respect to reversibility remains unclear, because the aetiopathogenesis has not yet been identified except for those cases of endocrine active ovarian neoplasms. In this field an intensified co-operation between clinicians and pathologists is necessary. Especially systematic case control studies, including endocrinology and determination of foaling rates may reveal further understanding resulting in efficient plans of treatments.