This report presents the first detection of canine circovirus (CanineCV) in South Korea, which was identified in a dog with hemorrhagic diarrhea. A 5-year-old male Golden Retriever presented with acute, watery and bloody diarrhea that had persisted for three weeks. Pathologically, granulomatous inflammation, fibrinoid vasculitis, and hemorrhagic foci were observed in the small intestine and mesenteric lymph nodes. Characteristic intracytoplasmic amphophilic inclusion bodies were observed in histiocytic cells within the granulomatous lesions. CanineCV was amplified by polymerase chain reaction from the small intestine, mesenteric lymph nodes, and fecal samples. A genomic analysis of the complete capsid gene from the Korean strain of CanineCV revealed that it shares the highest nucleotide and amino acid sequence similarities, at 94.2% and 94.1% respectively, with the American UCD3-478 isolate. Phylogenetic analysis based on the nucleotide sequence of the capsid gene classified the Korean strain as type 4 CanineCV. This case highlights the importance of genomic surveillance for emerging pathogens in South Korea and lays the groundwork for further research into the epidemiology and pathogenicity of CanineCV in canine enteric diseases.

Multiple autoimmune syndrome (MAS) refers to the occurrence of three or more autoimmune diseases in a patient. This case describes a 12-year-old neutered male Shih Tzu with fever and neutropenia, previously diagnosed with immune-mediated thrombocytopenia, immune-mediated hemolytic anemia, and inflammatory bowel disease. Blood tests revealed leukopenia and neutropenia, and immune-mediated neutropenia was suspected after ruling out other causes of neutropenia. The dog showed no response to antibiotics, but treatment with prednisolone (2 mg/kg q24h) led to improvement. This case highlights the potential for MASs to occur in dogs and underscores the importance of their recognition in the diagnosis and management of immune-mediated diseases.

In this paper, we explore diagnosing and treating osteosarcoma in the mammary gland using a combination of tyrosine kinase inhibitors (TKIs) and cyclophosphamide. A case involving a 14-year-old female mixed-breed dog with a 12.4 × 11 cm singular mass in the mammary region is discussed. Initial cytological analysis from a fine-needle aspiration suggested the possibility of mixed-type mammary carcinoma and carcinosarcoma. The mass was surgically excised and sent for histopathological examination, which confirmed it as extraskeletal osteosarcoma of the mammary gland. Following surgery, metronomic chemotherapy with cyclophosphamide and fibrocoxib was implemented, along with targeted therapy using toceranib and cyclophosphamide. Seven months post-chemotherapy, the dog exhibited lameness in the right hind limb and metastasis in the 4th thoracic spine. Within 10 months, the condition progressed to tetraparesis, leading to euthanasia 1 month later. This case highlights the need for differential diagnosis among mammary gland mixed-type carcinoma, carcinosarcoma, osseous metaplasia, and osteosarcoma in the context of osteocytes for accurate prognosis. The dog survived 332 days post-surgery with the chemotherapeutic regimen involving toceranib and cyclophosphamide, indicating the effectiveness of TKI and metronomic chemotherapy in extending survival beyond the median for extraskeletal osteosarcoma.

A 7-year-old neutered male Shih Tzu presented with acute onset of progressive tetraparesis and generalized muscle atrophy. Neurological examination, electromyography (EMG), and muscle biopsy revealed findings consistent with denervation-induced muscular atrophy. Based on these results, a tentative diagnosis of immune-mediated neurogenic myopathy was established. Immunosuppressive therapy with cyclosporine and mycophenolate mofetil led to a marked clinical improvement. However, relapse following discontinuation of therapy indicated the chronic relapsing nature of the disease. This case demonstrates the diagnostic value of EMG and muscle biopsy in identifying neuromuscular disorders and underscores the importance of a multimodal diagnostic approach for the accurate diagnosis and management of suspected neurogenic myopathies.

Doxorubicin is an effective chemotherapeutic agent widely used in veterinary oncology, particularly as part of the CHOP protocol for canine lymphoma. Despite its therapeutic benefit, cardiotoxicity remains a serious dose-limiting adverse effect. Although clinically significant cardiotoxicity is typically reported at cumulative doses of 150-240 mg/m 2 in dogs, functional cardiac deterioration has been observed at lower doses, with progression to congestive heart failure rarely reported. This case report describes doxorubicin-induced cardiotoxicity below the established cumulative threshold in a dog with multicentric lymphoma, which presented with overt clinical signs of congestive heart failure, including coughing, syncope, and pleural effusion. The dog also exhibited marked echocardiographic changes, including right atrial enlargement and a reduction in fractional shortening from 33% to 21% over 2 weeks, ultimately resulting in death 53 days after symptom onset. The clinical diagnosis was supported by the temporal relationship with doxorubicin administration and serial cardiac imaging findings. This case highlights that severe cardiotoxicity can occur even below traditionally accepted cumulative thresholds, reinforcing the importance of individualized, ongoing cardiac monitoring and early intervention, regardless of dose.