The purpose of this study was to examine the relationship between demyelination and cellular reactions in the cerebellum of Canine Distemper Virus (CDV)-infected dogs. We subdivided the disease staging by adding the degree of demyelination determined by Luxol Fast Blue staining to the previously reported disease staging from the acute stage to the chronic stage, and investigated the relationship between demyelination in the cerebellum and the number and histological changes in astroglia, microglia, and Purkinje cells in each stage. Reactions of astrocytes and microglia were observed at an early stage when demyelination was not evident. Changes progressed with demyelination. Demyelination initially began in the medulla adjoining the fourth ventricle and gradually spread to the entire cerebellum, including the lobes. CDV immune-positive granules were seen from the early stage, and inclusion bodies also appeared at the same time. CDV immune-positive reaction and inclusion bodies were observed in astrocytes, microglia, neurons, ependymal cells, and even leptomeningeal mononuclear cells. On the other hand, infiltration of CDV-immunoreactive particles from the pia mater to the gray matter and further into the white matter through the granular layer was observed from an early stage. Purkinje cells decreased from the intermediate stage, and a decrease in cells in the granular layer was also observed. There was no clear association between age and each stage, and the stages did not progress with age.

The purpose of this study was to examine the relationship between demyelination and glial cell responses in the cerebellum of CDV-infected dogs. We subdivided the disease staging by adding the degree of demyelination determined by LFB staining to the previously reported disease staging from the acute stage to the chronic stage, and investigated the relationship between demyelination in cerebellum and the number and histological changes of astroglia, microglia and Purkinje cells in each stage. Reactions of astrocytes and microglia were observed at an early stage when demyelination was not evident. Changes progressed with demyelination. Demyelination initially began in the medulla adjoining the fourth ventricle and gradually spread to the entire cerebellum, including lobes. CDV immune-positive granules were seen from the early stage, and inclusion bodies also appeared at the same time. CDV immune-positive reaction and inclusion bodies were observed in astrocytes, microglia, neurons, ependymal cells, and even leptomenin-geal mononuclear cells. On the other hand, infiltration of CDV immunoreactive particles from the pia mater to the gray matter and further into the white matter through the granular layer was observed from an early stage. Purkinje cells decreased from the intermediate stage, and a decrease in cells in the granular layer was also observed. There was no clear association between age and each stage, and the stages did not progress with age.

We performed an histological study on all cases of canine skin hemangiomas and hemangiosarcomas that were examined between 2018 and 2020. Of the 446 dogs with skin tumors examined, 25 were diagnosed with hemangiomas and 24 were diagnosed with hemangiosarcomas. Mixed-breed dogs were the most commonly affected by both tumors. The average ages of the dogs who were diagnosed with hemangiomas and hemangiosarcomas were 8.70 and 8.36 years, respectively, with the mean age for hemangiosarcomas being slightly higher; however, this difference was not statistically significant. Both types of tumors were more common in the trunk and limbs. Sex differences in tumor frequency were not detected in dogs with hemangiomas or hemangiosarcomas. Histologically, the mixed capillary and cavernous type was the most common in cases of hemangiomas, and the mixed capillary, cavernous, and solid type and the mixed cavernous and solid type were more common in hemangiosarcoma cases compared with the other types. In addition, epithelioid hemangiosarcomas were frequently detected.

We performed an epidemiological and histological study on all cases of canine skin hemangiomas and hemangiosarcomas examined between 2018 and 2020. Of the 446 dogs with skin tumors examined, 25 were diagnosed with hemangiomas and 24 were diagnosed with hemangiosarcomas. Mixed-breed dogs were the most commonly affected by both tumors. The average ages of the dogs diagnosed with hemangioma and hemangiosarcoma were 8.70 and 8.36 years, respectively, and the mean age for hemangiosarcoma was slightly older than that for hemangioma; however, this difference was not statistically significant. Both types of tumors were more common in the trunk and limbs. Sex differences in tumor incidence were not detected in dogs with hemangiomas or hemangiosarcomas. Histologically, the mixed capillary and cavernous type was the most common in cases of hemangiomas, and the mixed capillary, cavernous, and solid types and mixed cavernous and solid types were more common in hemangiosarcoma cases compared to the other types. In addition, epithelioid hemangiosarcomas were frequently detected.

Feline chronic gingivostomatitis (FCGS) is a painful inflammatory disease of the oral cavity in which partial-mouth or full-mouth extraction (PME or FME) is considered the standard treatment. However, longitudinal information regarding histopathologic and local immunologic changes after surgery remains limited. The aim of this pilot prospective study was to assess the clinical, hematologic, biochemical, histopathologic, and immunologic evolution of cats with FCGS following PME. Five cats diagnosed with FCGS were enrolled and followed longitudinally. Clinical response was assessed in the five cats using the Stomatitis Disease Activity Index (SDAI), together with hematologic, biochemical, and retroviral testing. Biopsies of the caudal oral mucosa were collected from three cats before surgery and 30 days after surgery for histopathologic evaluation using a previously described inflammatory scoring system. Immunolabeling of CD20, FoxP3, and IL-17 was quantified by digital image analysis. Clinical scores improved after PME, although the magnitude of the response varied among individuals. Persistent non-regenerative anemia and marked monocytosis were observed in cats positive for feline leukemia virus and/or feline immunodeficiency virus. Hyperglobulinemia was the most common biochemical abnormality. Histopathologic examination revealed moderate-to-marked lymphoplasmacytic inflammation associated with epithelial hyperplasia, edema, and, in the most severe cases, spongiosis and necrosis. Sequential biopsies demonstrated reductions in histologic inflammatory scores in two of three cats. CD20 immunolabeling decreased post-PME, whereas FoxP3 and IL-17 expression showed marked interindividual variability. This pilot prospective study provides preliminary observations on tissue changes in the early stages following PME.

Papillomaviruses induce epithelial hyperplasia and exophytic warts in dogs. In young immunocompetent animals, lesions are typically self‐limiting and regress spontaneously; however, persistent infections may rarely be associated with malignant transformation. An 18‐month‐old male beagle presented with rapidly developing papillomatous lesions involving the periocular region of the right eye and tongue. The main medial canthus mass was surgically debulked. Histopathology and immunohistochemistry supported a diagnosis of papillomavirus‐associated papilloma. A formalin‐inactivated autologous vaccine combined with a non‐specific immunostimulant (Zylexis) was administered weekly for 4 weeks. Progressive regression of residual lesions was observed, with complete clinical resolution by Day 28. There was no recurrence during the 18‐month follow‐up period. This case describes a potential adjunctive immunotherapeutic approach that may promote early regression of the canine papillomavirus and may warrant further evaluation in controlled clinical studies.