and Relevance: Severe necrosis and mild fibrosis were observed in the liver and forelimb skeletal muscles. Based on histological analysis, we diagnosed iron overload myopathy by secondary hemochromatosis. Secondary hemochromatosis with severe muscle atrophy and myositis is very rare, and this is the first report of iron-overload myopathy in a dog.

and Relevance: Severe necrosis and mild fibrosis were observed in the liver and forelimb skeletal muscles. Based on histological analysis, we diagnosed iron overload myopathy by secondary hemochromatosis. Secondary hemochromatosis with severe muscle atrophy and myositis is very rare, and this is the first report of iron-overload myopathy in a dog.

and Relevance: Severe necrosis and mild fibrosis were observed in the liver and forelimb skeletal muscles. Based on histological analysis, we diagnosed iron overload myopathy by secondary hemochromatosis. Secondary hemochromatosis with severe muscle atrophy and myositis is very rare, and this is the first report of iron-overload myopathy in a dog.

and Relevance: Severe necrosis and mild fibrosis were observed in the liver and forelimb skeletal muscles. Based on histological analysis, we diagnosed iron overload myopathy by secondary hemochromatosis. Secondary hemochromatosis with severe muscle atrophy and myositis is very rare, and this is the first report of iron-overload myopathy in a dog.

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.

A 12-year-old intact female Miniature Pinscher dog was presented to our hospital with a large mass in the right mammary gland. On computed tomography, several masses throughout the mammary glands and enlarged bilateral inguinal lymph nodes were confirmed. Right hemimastectomy was performed first, and mammary gland osteosarcoma with lymph node metastasis was diagnosed by histopathological examination. After consultation with the owner, left hemimastectomy was not performed, but chemotherapy with carboplatin was initiated. The dog was treated with carboplatin, a tyrosine kinase inhibitor, and mega-dose vitamin C therapy for approximately eight months. However, during the course of treatment, pulmonary metastasis, neurological signs, and periosteal reaction in the appendicular skeletons developed, and the patient died after several seizure episodes. This present case report describes the overall disease progression and treatment of mammary gland osteosarcoma in a dog.

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.

A 13-year-old, Maltese dog presented with syncope and lethargy. Abdominal ultrasonography demonstrated anechoic peritoneal effusion and hepatic congestion. A focal echogenic round mass compressing the right ventricle and atrium was observed on echocardiography. Cardiac tamponade and right ventricular outflow tract obstruction occurred. On computed tomography, a homogeneous soft-tissue structure compressing the right chamber without contrast enhancement, suspected to be loculated pericardial effusion. During pericardiocentesis, cardiac tamponade was resolved, and irregular pericardial thickening was noted. Pericardial effusion was exudate and gram-positive bacterial colonies were observed on cytology. A diagnosis of fibrinous pericarditis secondary to bacterial infection was established.

An 8-year-old, spayed female Persian cat weighing 3.6 kg presented with a lumbosacral mass and bilateral weight bearing hindlimb lameness. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a dumbbell-shaped heterogeneous mass extending through the internal surface of the ileum and surrounding the lumbosacral junction. CT also revealed extensive osteoproliferation and bone lysis of the sacrum, but no evidence of any pulmonary metastasis. Furthermore, MRI revealed a focal area in the spinal cord showing connection with the adjacent tumor, suggesting tumor invasion into the spinal cord. Low-grade myxoid chondrosarcoma was histopathologically diagnosed. This is the first report describing CT and MRI findings of spinal cord chondrosarcoma in veterinary medicine. This study suggests that combining CT with MRI is a more sensitive tool for evaluating spinal tumors than using CT or MRI alone.

Small B-cell lymphoma typically has a more favorable prognosis compared to diffuse large B-cell lymphoma (DLBCL). Here, we present the first documented case of canine DSBCL characterized by extensive lymphocyte infiltration in the spleen, leading to splenic rupture and death. A 10-year-old neutered male Shih Tzu presented with lethargy, skin lesions, and generalized lymphadenopathy. On the day of admission, the dog experienced shock, accompanied by bradycardia and hypotension, and subsequently died. Necropsy confirmed splenic rupture, and cytology, histopathology, and immunophenotyping of the lymph nodes confirmed the diagnosis of diffuse small B cell lymphoma (DSBCL). Similar neoplastic cells were identified in the spleen and inguinal skin, establishing a diagnosis of stage V lymphoma with multi-organ infiltration. This case shows that while non-DLBCL B-cell lymphomas are often indolent, certain subtypes, such as DSBCL, may exhibit aggressive behavior, emphasizing the need to carefully evaluate the extent of infiltration in such cases.