A 9-year-old Thoroughbred mare with normal external genitalia and regular oestrus symptoms was gynecologically examined prior to insemination. This primary examination revealed the presence of a hypoplastic uterus and the lack of normal ovaries, and the mare was therefore subjected to more detailed diagnostics, including endocrinological, genetic, and clinical tests. Diagnostic imaging with the use of ultrasonography and endoscopy confirmed the underdevelopment of internal genitalia. Analysis of circulating sex hormones revealed very low concentrations of progesterone and oestradiol. Finally, cytogenetic analysis showed the presence of non-mosaic X trisomy (65,XXX), an aneuploidy of sex chromosomes that is rarely detected in horses. This finding was also confirmed by molecular methods, including highly sensitive droplet digital PCR (ddPCR) and microsatellite markers genotyping. Our study reveals the need for gynaecological and genetic evaluation of broodmares, even if their phenotype (including developed external genitalia and oestrus symptoms) shows no signs of potential abnormalities.

Granulosa cell tumor (GCT) is a benign tumor which affects the mare\'s ovaries. In this report, a case of unilateral GCT in an ovary, which weighed 17.04 kg, of a 9-year-old Breton draft mare is described. A transrectal ultrasonography exam revealed a unilateral multi-cystic enlarged ovary. Laparoscopic ovariectomy was difficult due to enlargement of blood vessels in the ovarian broad ligament. The mare was necropsied, and the pathological changes in the GCT-affected ovary and unaffected ovary were evaluated. The ovarian mass in the GCT-affected ovary had a cribriform pattern and was positive for anti-Müllerian hormone (AMH) and its receptor (AMHR2). The contralateral ovary showed no follicular development and was negative for AMH. AMHR2 was positively expressed in stromal cells. The AMH concentration in plasma was 4,210 ng/ml. This is the first report showing the presence of AMH (2,210 ng/ml) in ascites fluid, and it also shows that laparoscopic ovariectomy might not be suitable for larger ovaries affected by a GCT. Ultrasonographic, endocrine, and histopathological analyses were helpful for making a definitive diagnosis of GCT in this mare.

Chronic endometritis is an inflammation in the inner layer of uterine mucosa, with or without an infectious process, which affects the animal\'s fertility but not its general health. A variety of treatments has been adopted over the years but to date, no effective cures have been able to renew the injured tissue. Since the defects in the fetal-maternal communication are caused by degenerative changes due to chronic endometrial inflammation, our working hypothesis was a new approach to this disease by the regenerative medicine using amniotic derived microvesicles (MVs) for their anti-inflammatory and regenerative effects. The MVs are responsible for horizontal transfer of genetic materials, including microRNA (miRNAs) that are involved in paracrine communication between origin cells and target cells. Thus, intrauterine MV infusion may be beneficial in degenerative chronic endometritis and in the fetal-maternal talk. The selected mare was an 11-year-old Friesian, with a history of failed pregnancies despite numerous insemination attempts. Punctual and evident heats characterized the reproductive history, but no insemination attempts had been made for many years. The first (failed) insemination was when the mare was 9-years-old. In the next two reproductive seasons, other attempts were made at regular intervals but none was successful. After a final insemination attempt using a stallion of proven fertility, the collection of an 8-day old embryo suggested that the mare was affected by implantation failure related to endometritis. The mare was treated with two cycles of intrauterine administration of amniotic-derived MVs. The success of the intrauterine administration of MVs was demonstrated by an improvement in the classification of endometritis and in a successful artificial insemination (AI) with implantation of an embryo, as detected at day 14 and with a pregnancy that is still ongoing. Probably, MVs were able to restore the injured endometrium and re-establish the proper communication for a successful embryo implantation.

An 18-year-old French Trotter mare was presented to the Clinique Equine, Ecole Nationale Vétérinaire d\'Alfort, for exploration of a 3-month-duration vaginal bleeding. A transrectal ultrasound examination identified a mass within the right uterine horn wall, which had been suspected during transrectal palpation. It was described as a firm heterogeneous intramural mass (7 × 12 cm) in the right uterine horn, located few centimeters cranially to the bifurcation. Hysteroscopy confirmed the ulcerated and irregular shape of the mass. A standing hand-assisted flank laparoscopy was performed to carry out a partial ovariohysterectomy. Two days after surgery, the mare presented with acute and severe signs of colic and was euthanized. Postmortem examination revealed a 720° small intestine volvulus at the mesenteric root, a left dorsal displacement of the large colon, and iliac and tracheobronchial lymph node hypertrophy. Histopathological examination of the removed uterine mass revealed a well-differentiated and infiltrating uterine adenocarcinoma, with lymph node metastasis. Uterine neoplasia, especially adenocarcinoma, is uncommon in the mare and can be successfully removed using a standing hand-assisted laparoscopic technique, which avoids the risks associated with general anesthesia and allows a histologic diagnosis of malignancy. In such cases, though, initial staging and identification of metastasis remain a challenge that will influence the treatment strategy.