吉田 佳倫

A 10-year-old spayed mixed breed dog presented with severe neurological signs. Computed tomography revealed a cranial mediastinal mass, osteolysis of the right second rib and second thoracic vertebra, tracheobronchial and mesenteric lymph node enlargement, pneumonia and pleural effusion. Magnetic resonance imaging detected lesions in the white matter of the right frontal lobe and left cerebral hemisphere with contrast-enhanced T1-weighted images showing demarcated enhancement. On cut section, the surface of the right cerebral frontal lobe and left cerebral hemisphere corticomedullary junctions were indistinct and the white matter was discoloured. Microscopically, multicentric granulomatous inflammation was seen in the brain, cranial mediastinal mass, masses on the right second rib, tracheobronchial and mesenteric lymph nodes, heart, kidneys, lungs and oesophagus. Necrosis and hyaline fungal structures were frequently observed in the centre of the granulomas. These fungi had septae, Y-shaped branching and were 2-3 μm in width. Sequence analysis of DNA from formalin-fixed paraffin-embedded samples identified the fungi as Schizophyllum commune. Based on these findings, this case was diagnosed as disseminated S. commune infection. This is the first report of granulomatous encephalitis caused by S. commune in a dog.

Three young adult cats with intermittent spinal hyperesthesia and paraparesis and diagnosed with spinal epidural arteriovenous fistula are described. In all 3 cases, magnetic resonance imaging (MRI) showed focal dilatation of the veins in the epidural space of the thoracic spinal cord, whereas computed tomography angiography (CTA) showed dilatation and enhancement from the intercostal vein to the azygos vein at the same site in the arterial phase. Dorsal laminectomy and occlusion of the interarcuate branches running across the dorsal aspect of the spinal cord were performed in all 3 cats to decompress the spinal cord, which resulted in a remission of clinical signs and no recurrence during 14 to 40 months of follow-up after surgery in all cases.

<sec><title>Case summary</title> A 4-year-old castrated male domestic shorthair cat with a continuous cough was brought to a private veterinary clinic for detailed examination. Radiography of the thoracic cavity revealed a severe radiopaque region in the caudal lobe of the right lung. At 108 days after the initial visit, CT showed a mass of 27 × 23 × 18 mm in the caudal lobe of the right lung. At that time, no abnormalities in other organs except for the lung were detected on CT and peripheral blood and blood biochemistry tests. The mass in the caudal lobe of the right lung was resected by lobectomy; it had a white surface and was firm. Histopathologically, the mass was non-encapsulated, showing an unclear boundary with surrounding tissues. The mass comprised large, round or polygonal neoplastic cells arranged in a diffuse pattern. Immunohistochemically, neoplastic cells were diffusely positive for CD20, feline leukaemia virus (FeLV) p27 and FeLV glycoprotein 70 but negative for CD3, CD204 and E-cadherin. Based on these findings, diffuse large B-cell lymphoma associated with FeLV infection was diagnosed. Although the cat showed no clinical signs of gastrointestinal or respiratory injury, a routine ultrasonography revealed thickening in the jejunum wall 196 days after lobectomy, and subsequent fine-needle aspiration examination confirmed high-grade lymphoma. </sec><sec><title>Relevance and novel information</title> This is the first report of primary pulmonary diffuse large B-cell lymphoma associated with FeLV infection in a young cat. </sec>

The feline AB blood group system (blood types A, B, and AB) encoding the cytidine monophosphate-N-acetylneuraminic acid hydroxylase (CMAH) gene is the most significant in transfusion medicine and hemolysis of the newborn for cats. Blood typing and cross-matching in pre-transfusion testing are crucial to determining blood compatibility and thus prevent hemolytic transfusion reactions. We here performed serological and genetic investigations to characterize blood samples from cats with discordant results for card agglutination (CARD) and the alloantibody agglutination test for blood typing in two cats (subjects K and R). Subject K showed incompatible cross-matching in pre-transfusion testing. Red blood cells from subjects K and R determined blood type B from the CARD method showed blood type AB by alloanti-A and alloanti-B antibodies in agglutination testing. Genomic DNA sequencing of the coding region (exons 1a to 14) for the cat CMAH gene showed that subject K had four mutations with heterozygosity at c.139C>T, c.179G>T, c.327A>C, and c.364C>T. Similarly, the CMAH gene of subject R carried six mutations with heterozygosity at c.142G>A, c.187A>G, c.268T>A, c.327A>C, c.773G>A and c.1603G>A, representing a new diplotype including a novel synonymous single nucleotide polymorphism (SNP) in exon 7 (c.773 G>A: Arg258Gln). The CMAH diplotype in subjects K and R was different from major diplotype in blood type B cats. This study is the first to report CMAH variants in cats with discordant blood types between CARD and TUBE methods. These results could assist in the classification of feline AB blood types for transfusion medicine to avoid blood incompatibilities.