Osteoinductive squamous cell carcinoma associated with a putative novel papillomavirus on the digit of a cat.

CASE HISTORY AND CLINICAL FINDINGS: An approximately 10-year-old, castrated male domestic short-haired cat developed swelling and ulceration of the second digit of the right front paw. Radiographs revealed a spherical soft tissue swelling with irregular distal margins that contained multiple lacy mineral opacities. The digit was amputated and submitted for histology. No recurrence has been observed 7 months after amputation. PATHOLOGICAL AND MOLECULAR FINDINGS: Histology revealed a moderately well-circumscribed proliferation of well-differentiated squamous cells arranged in trabeculae and nests. Numerous thin spicules of osseous metaplasia were visible throughout the neoplasm. Around 70% of the neoplastic cells contained papillomavirus-induced cell changes including large amphophilic cytoplasmic bodies and cells with shrunken nuclei surrounded by a clear halo. Intense p16CDKN2A protein immunostaining was visible within the neoplastic cells, suggesting papillomavirus-induced changes in cell regulation. A DNA sequence from a putative novel Taupapillomavirus type was amplified from the neoplasm. DIAGNOSIS: Osteoinductive squamous cell carcinoma associated with a putative novel papillomavirus type. CLINICAL RELEVANCE: The findings in this case increase the number of papillomavirus types known to infect cats, and the squamous cell carcinoma had histological features that have not been previously reported. The neoplasm was not as invasive as is typical for a squamous cell carcinoma and excision appeared curative. This is the first report of an osteoinductive squamous cell carcinoma of the skin of cats and the neoplasm had a unique radiographic appearance.

Squamous cell carcinoma of the anal sac in two cats.

This report describes two cases of feline anal sac squamous cell carcinoma. Cat 1 was managed with a multimodal approach combining surgical resection, radiation therapy and systemic therapy (toceranib phosphate; Palladia™) until local recurrence was identified at 236 days postsurgery. At that time, the cat received carboplatin. With the tumour being progressive, the cat was euthanased 552 days post initial surgery. Cat 2 was managed palliatively with a non-steroidal anti-inflammatory (meloxicam) and supportive medications. Unfortunately, with further decline in quality of life following initial diagnosis, the cat was euthanased 28 days later. Squamous cell carcinoma should be considered as a possible differential diagnosis when a cat is presented for investigation of an anal sac mass.

Unique presentation of normolipaemic cutaneous xanthoma in a cat.

CASE REPORT: A normolipaemic 7-year-old female spayed Domestic Shorthair was initially presented with a history of pruritus for several years and diagnosed with concurrent atopic dermatitis, flea bite hypersensitivity and adverse food reaction. The hypersensitivities were controlled with cyclosporin, allergen-specific immunotherapy, topical flea control and a restricted diet. Five months after initial presentation, the cat developed a non-healing nodular ulcerated cutaneous lesion in the left axilla and also developed immune-mediated haemolytic anaemic (IMHA). The IMHA was stabilised, but the axillary lesion persisted and progressed to a diffuse, firm, yellowed subcutaneous swelling over the ventral body approximately 20 months later. Histopathology was consistent with cutaneous xanthoma. The cat was normolipaemic and being fed a home-prepared diet of lean kangaroo meat and pumpkin to manage pruritus associated with adverse food reactions. No underlying malignancy was detected on routine screening tests. CONCLUSION: A diffuse, planar form of cutaneous xanthoma occurring without associated lipaemia has not been previously reported in cats.

In a shake of a lamb's tail: using genomics to unravel a cause of chondrodysplasia in Texel sheep.

Chondrodysplasia in Texel sheep is a recessively inherited disorder characterized by dwarfism and angular deformities of the forelimbs. A genome-wide association study using the Illumina OvineSNP50 BeadChip on 15 sheep diagnosed as affected and eight carriers descended from three affected rams was conducted to uncover the genetic cause. A homozygous region of 25 consecutive single nucleotide polymorphism (SNP) loci was identified in all affected sheep, covering a region of 1 Mbp on ovine chromosome 4. Seven positional candidate genes - including the solute carrier family 13 (sodium/sulphate symporters), member 1 (SLC13A1) - were identified and used to search for new SNPs for fine mapping of the causal locus. The SLC13A1 gene, encoding a sodium/sulphate transporter, was the primary candidate gene attributable to similar phenotypes observed in the Slc13a1 knockout mouse model. We discovered a 1-bp deletion of T (g.25513delT) at the 107 bp position of exon 3 in the SLC13A1 gene. Genotyping by direct sequencing and restriction fragment length polymorphism analysis for this mutation showed that all 15 affected sheep were g.25513delT/g.25513delT; the eight carriers were g.25513delT/T and 54 normal controls were T/T. The mutation g.25513delT shifts the open reading frame of SLC13A1 to introduce a stop codon and truncate C-terminal amino acids. It was concluded that the g.25513delT mutation in the SLC13A1 gene was responsible for the chondrodysplasia seen in these Texel sheep. This knowledge can be used to identify carriers with the defective g.[25513delT] allele to avoid at-risk matings to improve animal welfare and decrease economic losses.

On the Sulfation Pattern of Polysaccharides in the Extracellular Matrix of Sheep with Chondrodysplasia.

OBJECTIVE: Chondroitin sulfate is the major sulfated polysaccharide attached to the core protein, aggrecan, in the hyaline cartilage matrix. Sulfation of the cartilage matrix polysaccharide is vital for normal matrix integrity and compressive stiffness of the tissue and is therefore crucial to normal cartilage formation and consequently to endochondral ossification. Several forms of chondrodysplasia, a condition resulting in clear macroscopic deficiencies in the mechanical properties of the cartilage and characterized by reduced levels of sulfate, have been identified in both human beings and animals. DESIGN: In this study, the authors used capillary electrophoresis to investigate the sulfation state of extracted chondroitin sulfate polymers. RESULTS: Significantly, cartilage from affected sheep had a lower ratio of the chondroitin-derived enzymatically liberated disaccharides Δdi-mono4S to Δdi-mono6S, demonstrating reduced levels of chondroitin 4-sulfate, but not chondroitin 6-sulfate, in chondrodysplastic sheep compared to age-matched controls at all ages measured. CONCLUSION: This supports the hypothesis that a difference in chondroitin sulfate disaccharides is detectable in affected newborn lambs prior to the development of lesions.

Inherited abnormalities of skeletal development in sheep.

Inherited diseases of the skeleton are reported less often in sheep than in most other domestic animal species but are likely to occur more frequently than the veterinary literature would suggest. Although most are lethal or semi-lethal, the gene frequency for some of these diseases has reached surprisingly high levels in defined populations, presumably due either to the founder effect or the presence of a selective advantage of heterozygous individuals. This article reviews the clinical characteristics, pathology, mode of inheritance and molecular basis of skeletal diseases known to have a genetic aetiology in sheep. Inherited skeletal diseases of sheep are potential models for studying the treatment of similar diseases in humans.