Identification of focal adenomyosis as a uterine lesion in two dogs

Endometrial hyperplasia and pyometra in captive lions (Panthera leo) and tigers (Panthera tigris)

Endometrial hyperplasia (EH) is a pathologic condition of the uterus with increased endometrial gland to stroma ratio compared to normal cyclic uterine proliferation. In domestic animals, EH often involves cystic distension of proliferating endometrial glands and may be concurrent with pyometra. In large captive nondomestic felids, an association between EH and pyometra is common; however, detailed species differences between the histological uterine findings in lions (Panthera leo) and tigers (Panthera tigris) and clinical manifestations have yet to be described. Uterine sections from 14 lions and 24 tigers with EH and/or pyometra were scored for several histological parameters and clinical histories were recorded. The percentage of endometrium affected by hyperplasia, endometrial gland to stroma ratio, and adenomyosis were significantly (P = .0385, P = .0008, and P = .0463, respectively) more severe in lions compared to tigers as univariate analytes. Although tubular complexity was not statistically significant (P = .3254), when combined as a proposed EH grading scheme, these 4 features confirmed lions had significantly (P = .0068) more severe EH compared to tigers. Endometrial hyperplasia severity significantly correlated with inflammation/pyometra severity when controlling for species (P = .0203). A significant correlation exists between pyometra-associated clinical sign severity and the presence of pyometra in tigers, (P = .0026) but not in lions (P = .1144). There was no statistical difference in the severity of clinical signs associated with pyometra between these species (P = .1986). This proposed grading scheme may have clinical utility in providing a more consistent and objective evaluation of EH in large captive felids.

Unveiling the Pathogenesis of Adenomyosis through Animal Models

Background: Adenomyosis is a common gynecological disorder traditionally viewed as “elusive”. Several excellent review papers have been published fairly recently on its pathogenesis, and several theories have been proposed. However, the falsifiability, explanatory power, and predictivity of these theories are often overlooked. Since adenomyosis can occur spontaneously in rodents and many other species, the animal models may help us unveil the pathogenesis of adenomyosis. This review critically tallies experimentally induced models published so far, with a particular focus on their relevance to epidemiological findings, their possible mechanisms of action, and their explanatory and predictive power. Methods: PubMed was exhaustively searched using the phrase “adenomyosis and animal model”, “adenomyosis and experimental model”, “adenomyosis and mouse”, and “adenomyosis and rat”, and the resultant papers were retrieved, carefully read, and the resultant information distilled. All the retrieved papers were then reviewed in a narrative manner. Results: Among all published animal models of adenomyosis, the mouse model of adenomyosis induced by endometrial–myometrial interface disruption (EMID) seems to satisfy the requirements of falsifiability and has the predictive capability and also Hill’s causality criteria. Other theories only partially satisfy Hill’s criteria of causality. In particular, animal models of adenomyosis induced by hyperestrogenism, hyperprolactinemia, or long-term exposure to progestogens without much epidemiological documentation and adenomyosis is usually not the exclusive uterine pathology consequent to those induction procedures. Regardless, uterine disruption appears to be a necessary but not sufficient condition for causing adenomyosis. Conclusions: EMID is, however, unlikely the sole cause for adenomyosis. Future studies, including animal studies, are warranted to understand how and why in utero and/or prenatal exposure to elevated levels of estrogen or estrogenic compounds increases the risk of developing adenomyosis in adulthood, to elucidate whether prolactin plays any role in its pathogenesis, and to identify sufficient condition(s) that cause adenomyosis.

[Uterine serosal inclusion cysts in the dog - case report and literature review of canine uterine cysts]

In bitches, uterine cysts are usually associated with pathological conditions. Serosal inclusion cysts of the uterus represent an exception to this rule. These thin-walled cysts develop on the uterine surface and occur either as single or multiple cysts. The cysts lack endocrine activity and usually do not cause clinical symptoms. Their occurrence shows no association to the estrus cycle. Serosal inclusion cysts are mainly found in older multiparous bitches and large breeds are more often affected. Diagnosis of serosal inclusion cysts may be achieved by transabdominal sonography. Differentiation between uterine and ovarian serosal inclusion cysts is possibly challenging as serosal inclusion cysts are often located in the area of the tip of the uterine horn. This report presents the case of a breeding bitch with multiple uterine serosal inclusion cysts detected during caesarean section. The concentrations of estradiol 17β and progesterone in the cyst fluid corresponded to the blood concentrations of these hormones in a bitch during parturition. The concentrations of total calcium, zinc, copper, and iron in the cyst fluid were below the reference values in canine blood whereas the concentrations of magnesium, phosphorus, sodium, and potassium in the cyst fluid were comparable to pertaining blood levels.

Animal Models of Adenomyosis

Adenomyosis is a nonmalignant uterine disorder in which endometrial tissue exists within and grows into the myometrium. Animal models have generated limited insight into the still-unclear pathogenesis of adenomyosis, provided a platform for preclinical screening of many drugs and compounds with potential as therapeutics, and elucidated mechanisms underlying the pain and fertility issues that occur in many women with the disease. Spontaneous adenomyosis has been studied in nonhuman primates, primarily in the form of case reports. Adenomyosis is routinely experimentally induced in mice through methods such as neonatal tamoxifen exposure, pituitary engraftment, and human tissue xenotransplantation. Several studies have also reported hormonal or environmental toxicant exposures that give rise to murine adenomyosis, and genetically engineered models have been created that recapitulate the human-like condition, most notably involving alteration of β-catenin expression. This review describes the animal models for adenomyosis and their contributions to our understanding of the factors underpinning the development of symptoms. Animal models represent a unique opportunity for understanding the molecular basis of adenomyosis and developing efficacious treatment options for affected women. Herein, we assess their different potentials and limitations with regard to identification of new therapeutic interventions and reflect on future directions for research and drug validation.

Concurrent occurrence of granulosa cell tumor, uterine adenomyosis, cystic endometrial hyperplasia and uterine serosal inclusion cyst in a bitch

An eleven-year-old Doberman-German Shepherd mixed bitch was presented with vulvar enlargement, vaginal discharge, and bleeding for two months and a week before, respectively. The dog was operated for routine ovariohysterectomy. During the surgery, a liquid-filled sac was observed on the ventrolateral border of the right uterine horn. The sac was ligated and excised. The uterine horns and ovaries were stained for histopathological evaluation. Granulosa cell tumor (GCT), adenomyosis (CUA), endometrial cystic hyperplasia (CEH), and uterine serosal inclusion cyst (USC) were diagnosed through histopathology assessment. Following up, 12 weeks after surgery revealed that the patient was in good condition with a good appetite and without any vaginal discharge. It seems the initial problem of the present bitch and the main cause of clinical signs was GCT. Probably, other abnormal conditions including CUA, CEH, and USC occurred as a result of hormonal disturbance associated with GCT. This report described the concurrent occurrence of GCT, CUA, CEH, and USC in a bitch as it has not been reported before.

Radiographic and ultrasonographic findings of uterine neoplasms in nine dogs

The records of nine female intact dogs with histologically confirmed uterine tumors were reviewed retrospectively, and the related radiographic and ultrasonographic signs of the lesions detected were recorded. Radiography revealed a soft-tissue opacity between the urinary bladder and colon in six of seven dogs with uterine body and/or cervical tumors, and a soft-tissue opacity in the midventral abdomen in two dogs with uterine horn tumors. Ultrasonography revealed masses in all dogs with uterine body/cervical tumors and could delineate the origin of the mass in one of two dogs with uterine horn tumors. The mass was characterized ultrasonographically as solid in three dogs (all leiomyomas), solid with cystic component in four dogs (two adenocarcinomas, one leiomyoma, and one fibroleiomyoma), and cystic in two (both leiomyomas). Hyperechoic foci in the mass were observed in three dogs. Ultrasonography was a useful method for demonstrating uterine body and/or cervical tumors. However, it was not possible to ascertain sonographically that a mass originated in a uterine horn unless there was associated evidence of uterine horn to which the mass could be traced. The ultrasonographic appearance of uterine tumors was variable, and the type of neoplasm could only be determined by taking biopsies of the mass.

Uterine adenomyosis in southern three-banded armadillos (Tolypeutes matacus)

Uterine adenomyosis was diagnosed in five southern three-banded armadillos (Tolypeutes matacus) from four different zoological collections in North America between 1995 and 2012. Two cases were diagnosed after ovariohysterectomy and histopathologic evaluation of the uteri, and the remaining cases were identified incidentally at the time of postmortem examination. Animals ranged from 5 to 14 yr of age at the time of diagnosis. Of armadillos diagnosed before postmortem examination, clinical signs included weakness, collapse, anemia, and vulvar discharge. Histopathologic evaluation of the uteri revealed well-developed, irregular endometrial glands extending into the myometrium and occasional hemorrhage within these glands. The two cases diagnosed antemortem were successfully treated with ovariohysterectomy. To the authors' knowledge, this condition has not been previously reported in Xenarthra, including armadillos.

Unilateral uterine torsion secondary to an inflammatory endometrial polyp in the bitch

A 9-year-old bitch was presented because of lethargy and abdominal distension. Abdominal ultrasound revealed an enlarged, fluid-filled uterus and associated mass. Subsequent exploratory laparotomy revealed unilateral uterine torsion involving the mass. Recovery following ovariohysterectomy was uneventful and the histopathological diagnosis was of a benign endometrial inflammatory polyp. Reports of uterine torsion in the English-language literature are reviewed to identify factors associated with the incidence of uterine torsion. The aetiology of the cystic endometrial hyperplasia/pyometra complex and its possible role in the development of inflammatory polypoid lesions in the bitch is also discussed.

Canine Uterine Leiomyoma with Epithelial Tissue Foci, Adenomyosis, and Cystic Endometrial Hyperplasia

An 11-year-old Labrador Retriever bitch with a history of intermittent, sanguineous vaginal discharge of a six-month duration was presented. During exploratory laparotomy, two well-delineated, intramural masses were identified bilaterally in the uterine horns. Histopathologic examination of the mass on the left horn showed that it was a typical leiomyoma. However, the second mass appeared with an unusual coexistence of histological lesions, involving epithelial tissue foci, mild focal adenomyosis, and cystic endometrial hyperplasia. Interestingly, such combination was never encountered before in dogs. Although uterine leiomyoma is quite usual in the reproductive system of female dogs, this case resembled relevant cases of human uterine adenomyomas in morphology, and thus it was offered a similar tentative diagnosis.

Spontaneous adenomyosis in the chimpanzee (Pan troglodytes): a first report and review of the primate literature: Case Report

Adenomyosis is a non-neoplastic condition characterized by the presence of ectopic endometrium in the myometrium with hyperplasia of adjacent smooth muscle. Common symptoms in women include debilitating pelvic pain and abnormal uterine bleeding, and the condition has been paradoxically associated with both multiparity and subfertility. Adenomyosis spontaneously occurs in humans and some non-human primates, including the baboon and macaque, where it has been associated with primary infertility and the presence of endometriosis. No cases of adenomyosis have been previously reported in Pongidae such as gorilla, orangutan or chimpanzee. We here describe two cases of naturally occurring adenomyosis in the chimpanzee (Pan troglodytes) and briefly review the literature regarding the presence of adenomyosis in non-human primate species.

Experimental adenomyosis

Adenomyosis has been reported in a number of different animal species, whereas endometriosis appears limited to humans and non-human primates. This suggests a different aetiology of the two conditions. Adenomyosis develops spontaneously in certain strains of laboratory mice. Its incidence in mice can be markedly enhanced by systemic exposure to various hormonal agents, including prolactin, progesterone, synthetic progestins, certain oestrogenic agents, as well as tamoxifen and toremifene. The precise hormonal changes necessary remain unclear, although the evidence suggests that adenomyosis in this model is not due to a simple oestrogenic effect. Study of the pathological and molecular alterations in this model indicates that disturbances to the uterine stroma, blood vessels and myometrium are also important factors in the development of adenomyosis.