Pathological features of hepatic portal venous gas in a cat.

An 8-year 8-month-old castrated male Munchkin presented with vomiting, anorexia and hypoactivity. Computed tomography revealed excessive gas accumulation within the intestinal lumen and gas bubbles in the liver, spleen, and portal venous system, indicating hepatic portal venous gas. The cat died without any significant improvement, and mild splenomegaly was found at necropsy. Histologically, multiple gas vacuoles were diffusely observed in the liver and spleen. In the stomach, multiple gas vacuoles and scattered focal ulcers were detected within the mucosa. Multifocal hemorrhage was noted in the small and large intestines, whereas gas vacuoles were not present. Based on these findings, a gastric ulcer under high gas pressure may have provided an entry point for gas into the portal venous system.

Hepatosplenic T-cell lymphoma with hepatocytotropism in a cat.

CASE SUMMARY: A 14-year 3-month-old spayed female mixed-breed cat presented with jaundice, anaemia and thrombocytopenia. Haemophagocytic syndrome associated with lymphoma was suspected after cytological examination of the spleen. Despite treatment with prednisolone, L-asparaginase and nimustine, the cat died 176 days after the initial presentation. Necropsy revealed splenomegaly and hepatomegaly, without lymphadenopathy. Histopathologically, neoplastic lymphoid cells infiltrated the hepatic sinusoid and splenic sinus. The neoplastic lymphoid cells showed marked hepatocytotropism and contained erythrocytes, which was also confirmed by electron microscopy. Immunohistochemically, neoplastic lymphoid cells were positive for CD3, TIA1 (GMP-17) and granzyme B, and negative for CD8, CD20, CD56, CD57, CD79a and Iba1. Based on these findings, the cat was diagnosed with hepatosplenic T-cell lymphoma (HS-TCL) with hepatocytotropism. RELEVANCE AND NOVEL INFORMATION: This case shows cytotoxic immunophenotype of HS-TCL in a cat, which has not been demonstrated before. Severe hepatocytotropism and haemophagocytosis of the neoplastic cells were likely to be associated with jaundice and anaemia, respectively, and the poor outcome of the present case.

Successful treatment and long-term follow up of idiopathic immune-mediated polyarthritis with mycophenolate mofetil in a cat.

CASE SUMMARY: A 7-year-old neutered male Norwegian Forest Cat was presented with decreased appetite and activity, weight loss, fever, neutrophilia and hyperglobulinaemia. A physical examination showed painful stifle joints and enlarged popliteal lymph nodes. Blood examination showed neutrophilia, hyperglobulinaemia and increased serum amyloid A. Urinalysis, thoracic and abdominal radiographs, and abdominal ultrasonography were unremarkable. Synovial fluid from the knee joints had diminished viscosity and revealed neutrophilic inflammation on the smear. There was no evidence of infection in a microbiological culture of the synovial fluid. A diagnosis of idiopathic immune-mediated polyarthritis (IMPA) was made. Prednisolone was initiated at 2 mg/kg q24h PO and tapered with additional immunosuppressants (leflunomide, ciclosporin A and methotrexate); however, prednisolone could not be discontinued. Informed consent was obtained from the owner and mycophenolate mofetil (MMF) at a dosage of 10 mg/kg q12h PO was initiated on day 798. There were no adverse effects of MMF and prednisolone was discontinued on day 1183. Clinical signs resolved and the cat's general condition remained stable with MMF alone at a dosage of 10 mg/kg q48h PO on day 1600. RELEVANCE AND NOVEL INFORMATION: There is limited information describing feline IMPA and its treatment options other than the use of prednisolone. This is the first report of the successful treatment and long-term follow-up of feline IMPA with MMF. MMF may be a safe and effective option as an additional immunosuppressant in feline IMPA.

Cutaneous epitheliotropic T-cell lymphoma with systemic dissemination in a dog.

Cutaneous epitheliotropic T-cell lymphoma (CETL) is characterized by neoplastic T-cell infiltration of the epidermis, adnexal structures, and oral mucosa. The objective of this report was to describe the pathological findings of a canine case of terminal-stage CETL. A 10-year-old, mixed-breed, neutered male dog was presented with erosion of the oral mucosa and mucocutaneous junction. The dog was diagnosed with CETL with no evidence of metastasis. Despite chemotherapy, the dog was re-presented with oral pain, vomiting, and diarrhea, and died 17 months after the first visit to the hospital. A complete autopsy was performed. Histologic examination of the primary lesion and systemic organs was performed. Gross examination revealed an advanced-stage oral lesion. Distinct tumor formation was not observed in the primary sites and systemic organs. Histologically, the primary oral lesion was characterized by massive intraepithelial infiltration of a large number of neoplastic lymphocytes. The neoplastic cells in the metastatic sites also showed exclusive epitheliotropic proliferation in organs, including the trachea, tonsils, esophagus, stomach, small intestine, colon, anal mucosa, liver, pancreas, kidneys, urinary bladder, prostate gland, ear canals, and auricular and ventral skin. Immunohistochemically, the neoplastic cells were positive for CD3 and negative for CD20 as well as CD79α, supporting a diagnosis of CETL with systemic dissemination. In canine CETL with systemic signs, systemic metastasis should be considered even without evident mass formation. Neoplastic lymphocytes of CETL showed distinct epitheliotropism even in the systemic metastatic sites.

Characterization of a canine tetranucleotide microsatellite marker located in the first intron of the tumor necrosis factor alpha gene.

A polymorphic tetranucleotide (GAAT)n microsatellite in the first intron of the canine tumor necrosis factor alpha (TNFA) gene was characterized in this study; 139 dogs were analyzed: 22 Beagles, 26 Chihuahuas, 20 Miniature Dachshunds, 24 Miniature Poodles, 22 Pembroke Welsh Corgis and 25 Shiba Inus. We detected the presence of the 4 alleles (GAAT)5, (GAAT)6, (GAAT)7 and (GAAT)8, including 9 of the 10 expected genotypes. The expected heterozygosity (He) and the polymorphic information content (PIC) value of this microsatellite locus varied from 0.389 to 0.749 and from 0.333 to 0.682, respectively, among the 6 breeds. The allelic frequency differed greatly among breeds, but this microsatellite marker was highly polymorphic and could be a useful marker for the canine TNFA gene.

Identification of cell surface antigen expression in canine hepatocellular carcinoma cell lines.

The characteristics of surface antigens in canine hepatocellular carcinoma (cHCC) have not been clarified. The objective of this study was to investigate surface antigens, which are considered as stem/progenitor or cancer cell markers, in cHCC cell lines. Expression of various antigens including CD29, CD34, CD44, CD90, CD133 and Dlk-1 was assessed in four cHCC cell lines by flow cytometry. CD44, CD133 and Dlk-1 expression was detectable in all cell lines, and three cell lines expressed CD29. These results indicate that CD29, CD44, CD133 and Dlk-1 have potential as suitable markers in cHCC identification, suggesting that these findings will contribute to the establishment of an early diagnostic tool for the identification of hepatocellular maturation processes.

Accumulation of xenotransplanted canine bone marrow cells in NOD/SCID/γc(null) mice with acute hepatitis induced by CCl4.

Bone marrow cell infusion (BMI) has recently been suggested as an effective therapy for refractory liver disease; however, the efficiency of BMI using canine bone marrow cells (cBMCs) has not been reported. We evaluated the accumulation potential of cBMCs in a mouse model of acute liver failure. Acute hepatitis was induced by carbon tetrachloride (CCl4) treatment in NOD/SCID/γc(null)(NOG) mice and wild-type (WT) C57BL mice, and the characteristics of liver dysfunction and the degree of hepatic injury and regeneration were compared between the two mouse models. Next, female CCl4-treated NOG mice were xenotransplanted with male PKH26-labeled cBMCs, and the potential of cBMCs to accumulate in injured liver tissue compartments was examined. Fluorescence microscopy was performed to histologically detect the infused cBMCs, and DNA polymerase chain reaction was performed for detection of the male Y chromosome (SRY gene) in the recipient female NOG mice. The number of PKH26-positive cBMCs transplanted in the liver tissue gradually increased in the NOG mice. The infused cBMCs were located in the necrotic area of the liver at an early stage after transplantation, and most had accumulated a week after transplantation. However, the therapeutic efficacy of the xenotransplantation remained unclear, because no significant differences were observed concerning the extent liver injury and regeneration between the cBMC-transplanted and saline control mice. These results suggest that cBMCs will specifically accumulate in injured liver tissue and that BMC transplantation may have the potential to repair liver deficiency.