Myocarditis is a disease caused by numerous etiological factors and characterized by a non-specific course. The only method allowing for precise characterization of inflammatory changes is the histopathological examination of heart muscle specimens. The study was conducted on heart muscle preparations from 11 dogs with ante-mortem diagnosis of cardiac disease. Animals presented with a poor response to an applied treatment or had suspected sudden cardiac death. The heart specimens were taken post-mortem, preserved and stained with haematoxylin and eosin. Subsequently, the presence and intensity of changes, i.e. inflammatory infiltration, the amount of connective tissue and features of cardiomyocyte degeneration were estimated. The specimens from dogs suspected of having a myocarditis of bacteriological etiology underwent additional bacteriological and immunohistochemical examination. The examination revealed an inflammatory infiltration of variable intensity combined with the degenerative changes in all dogs. There were vegetative and abnormal cystic forms of Borrelia burgdorferi sensu lato in 6 dogs. A Staphylococcus aureus infection was confirmed in one dog and an acute coronary syndrome with neutrophil infiltration was revealed in another one. Although the clinical pattern in patients with myocarditis is diverse, the definitive morphological diagnosis is made based on the histopathological examination. This examination can lead to a better understanding of the pathogenesis of the disease. To the best of our knowledge, this is the first description of myocarditis combined with the presence of spore forms of Borrelia burgdorferi sensu lato in the heart specimens of dogs.

Dilated cardiomyopathy (DCM) and chronic mitral valve disease (CMVD) in dogs are associated with heart chamber enlargement, also of the left atrium. DCM is often accompanied by rhythm disturbances (mainly atrial fibrillation or ventricular arrhythmias). In CMVD, arrhythmias are observed less frequently. It is still unclear whether left atrial enlargement in these diseases results from volume overload or if it is also connected with other factors (e.g. rhythm disturbances). This study was conducted on the left atrial myocardial specimens from 31 dogs, including those from 16 dogs with clinically diagnosed DCM and 15 dogs with CMVD. After fixation and staining (using haematoxylin-eosin and Masson-Goldner trichrome stain), the specimens underwent evaluation. Parenchymal changes (fibrosis, fatty infiltration, and vessel narrowing), degenerative changes (loss of striation, changes in cardiomyocyte structure, and abnormal cell nuclei) and the presence of inflammatory infiltrates were assessed. More interstitial fibrosis (median 4 vs. 2.5 grid fields; p < 0.05) and less perivascular fibrosis (median score 1 vs. 2; p < 0.05) was observed in the DCM group compared to the CMVD group. Moreover, less distinct vessel narrowing was observed in the DCM group than in the CMVD group (median lumen area ratio 0.3 vs. 0.26 respectively; p < 0.05). Dogs with DCM showed more strongly defined degenerative changes than the CMVD dogs (median nuclei enlargement score 3 vs. 1, median loss of striation score 3 vs. 2 and median structural alterations score 3 vs. 2, respectively; p < 0.05). The obtained results indicate a different nature of changes occurring in the left atrial myocardium of dogs with DCM compared to dogs with mitral valve disease, including differences in vessel narrowing, cardiomyocyte degeneration and in the distribution of connective tissue.

Hyperthyroidism is considered the most common endocrinopathy in middle-aged and old cats. The increased level of thyroid hormones influences many organs, including the heart. Cardiac functional and structural abnormalities in cats with hyperthyroidism have indeed been previously described. Nonetheless, myocardial vasculature has not been subjected to analysis. Also, no comparison with hypertrophic cardiomyopathy has been previously described. Although it has been shown that clinical alterations resolve after the treatment of hyperthyroidism, no detailed data have been published on the cardiac pathological or histopathological image of field cases of hyperthyroid cats that received pharmacological treatment. The aim of this study was to evaluate the cardiac pathological changes in feline hyperthyroidism and to compare them to alterations present in cardiac hypertrophy due to hypertrophic cardiomyopathy in cats. The study was conducted on 40 feline hearts divided into three groups: 17 hearts from cats suffering from hyperthyroidism, 13 hearts from cats suffering from idiopathic hypertrophic cardiomyopathy and 10 hearts from cats without cardiac or thyroid disease. A detailed pathological and histopathological examination was performed. Cats with hyperthyroidism showed no ventricular wall hypertrophy in contrast to cats with hypertrophic cardiomyopathy. Nonetheless, histological alterations were similarly advanced in both diseases. Moreover, in hyperthyroid cats more prominent vascular alterations were noted. In contrast to hypertrophic cardiomyopathy, the histological changes in hyperthyroid cats involved all ventricular walls and not mainly the left ventricle. Our study showed that despite normal cardiac wall thickness, cats with hyperthyroidism show severe structural changes in the myocardium.

Neoplastic lesions of the mammary gland, lymph nodes, or oral cavity in African pygmy hedgehogs (Atelerix albiventris) are common in captive animals. Chemotherapy and radiotherapy protocols have not yet been established for the African pygmy hedgehog. Thus, surgical resection is the current treatment of choice in this species. A 5-year-old male African pygmy hedgehog showed multiple erythematous, round small tumors located in the oral cavity, on both sides of maxilla. The treatment of choice was surgical resection of tumors using a surgical knife under general anesthesia. Excised neoplastic lesions were diagnosed as peripheral odontogenic fibroma by histopathology. Six months after surgery relapse of tumors in the oral cavity was not observed. The treatment adopted in this case report is safe for the patient and provides the best solution for mild proliferative lesions of the oral cavity. To our knowledge this is the first report of surgical resection of oral tumors (peripheral odontogenic fibroma) in the African pygmy hedgehog.

Background/Aim: Mammary neoplasms, like breast neoplasms in women, are one of the most common tumours in female dogs. Cancer-associated fibroblasts (CAFs) found in the tumour stroma play a role in angiogenesis and increase cell migration, contributing to tumour growth and progression, as well as metastasis. The aim of our work was to determine the level of periostin (POSTN) expression in CAFs in mammary tumours of female dogs. Materials and Methods: The research material consisted of 77 carcinomas and 24 adenomas of the mammary ridge in female dogs. Immunohistochemistry tests were performed using antibodies directed against the antigens POSTN, Ki-67, ERB-B2 receptor tyrosine kinase 2 (HER2), vimentin, and alpha smooth muscle actin (αSMA). Expression of POSTN at the mRNA level was determined using real-time polymerase chain reaction methods in 20 cases of mammary neoplasms. Results: Expression of POSTN in CAFs was observed in 92% of mammary cancer samples and in 25% of mammary adenoma samples in female dogs. A statistically significant increase in POSNT expression in CAFs was found in the carcinomas compared with mammary adenomas in female dogs. Expression of POSTN in CAFs in mammary carcinomas in female dogs positively correlated with the histological malignancy grade of tumours and the expression of Ki-67 proliferative antigen. Conclusion: Our results suggest a role of POSTN on the pathogenesis of mammary tumours in female dogs. Moreover, POSTN may prove to be a useful marker in the evaluation of cancerous stroma of mammary tumours in female dogs, and may have prognostic significance.

Introduction. The steady increase of dogs with diagnosed testicular neoplasms observed in recent years prompted us to carry out immunohistochemical (IHC) studies for their better characterization. The aim of the study was to analyze most common canine testicular neoplasms (seminomas, Leydig cell and Sertoli cell tumors) with selected IHC markers and to compare the expressions of these proteins in corresponding canine and human testicular tumors. Material and methods. Studies were carried out on testicular canine tumors: 40 cases of seminoma, 40 cases of Leydig cell tumor and 40 cases of Sertoli cell tumor. Moreover, 15 cases of human seminomas and 5 cases of human Leydig cell tumors were also analyzed. Immunohistochemistry was performed on paraffin sections by standard technique using monoclonal anti-human antibodies against E-cadherin, inhibin- α , calretinin and Ki-67. The slides were subjected to computer-aided image analysis and the intensity of the immunoreactivity was assessed by a semi-quantitative scoring system. Results. Due to the very low prevalence of the Sertoli cell-derived tumors in the human population, we were able to examine the markers’ expression only in the canine gonadal tumors. We revealed that, apart from E-cadherin in Leydig cell tumors and calretinin in seminomas, the expression of all the analyzed markers in canine and human testicular tumors was similar. E.g. there was no immunoexpression of inhibin- α in 75% of canine and 100% of human cases of seminoma. The immunoreactivity of Ki-67 was intense in 40% of canine and 60% of human seminomas. Immunoexpression of inhibin- α in Leydig cell tumor was intense in 70% of canine and 100% of human cases, respectively. Also the immunoreactivity of calretinin was intense in 75% of cases of canine and 100% of human Leydig cell tumors. In 50% of canine and 40% of human Leydig cell tumors, the immunoexpression of Ki-67 was weak. Conclusions. The applied anti-human monoclonal antibodies against common antigens and markers of human testicular neoplasms could be routinely used for the immunohistochemical evaluation of canine testicular tumors. Introduction. The steady increase of dogs with diagnosed testicular neoplasms observed in recent years prompted us to carry out immunohistochemical (IHC) studies for their better characterization. The aim of the study was to analyze most common canine testicular neoplasms (seminomas, Leydig cell and Sertoli cell tumors) with selected IHC markers and to compare the expressions of these proteins in corresponding canine and human testicular tumors. Material and methods. Studies were carried out on testicular canine tumors: 40 cases of seminoma, 40 cases of Leydig cell tumor and 40 cases of Sertoli cell tumor. Moreover, 15 cases of human seminomas and 5 cases of human Leydig cell tumors were also analyzed. Immunohistochemistry was performed on paraffin sections by standard technique using monoclonal anti-human antibodies against E-cadherin, inhibin- α , calretinin and Ki-67. The slides were subjected to computer-aided image analysis and the intensity of the immunoreactivity was assessed by a semi-quantitative scoring system. Results. Due to the very low prevalence of the Sertoli cell-derived tumors in the human population, we were able to examine the markers’ expression only in the canine gonadal tumors. We revealed that, apart from E-cadherin in Leydig cell tumors and calretinin in seminomas, the expression of all the analyzed markers in canine and human testicular tumors was similar. E.g. there was no immunoexpression of inhibin- α in 75% of canine and 100% of human cases of seminoma. The immunoreactivity of Ki-67 was intense in 40% of canine and 60% of human seminomas. Immunoexpression of inhibin- α in Leydig cell tumor was intense in 70% of canine and 100% of human cases, respectively. Also the immunoreactivity of calretinin was intense in 75% of cases of canine and 100% of human Leydig cell tumors. In 50% of canine and 40% of human Leydig cell tumors, the immunoexpression of Ki-67 was weak. Conclusions. The applied anti-human monoclonal antibodies against common antigens and markers of human testicular neoplasms could be routinely used for the immunohistochemical evaluation of canine testicular tumors.