Feline Epithelial Tumors of Skin and Subcutis
Basal cell carcinoma
Papilloma
Munday JS; Hanlon EM; Howe L; Squires RA; French AF(2007) Feline Cutaneous Viral Papilloma Associated with Human Papillomavirus Type 9 Vet Pathol 2007 44: 924-927.
Typical papilloma
On skin of head
HPV9 associatedViral plaques (Bowens)
Cats develop viral plaques in haired skin, and many are multiple. Progression to carcinoma in situ and the invasive squamous cell carcinoma or basal cell carcinoma or basosquamous carcinoma is common.
Originally the intraepidermal carcinomas were called Bowen's disease after the human condition. These are now frequently called bowenoid in situ carcinoma (BISC).
The lesions are of the epidermis and follow the infundibulum of the hair follicles. The normal epidermis and infundibulum is replaced by cell resembling basal cells - they are hyperchromatic and have minimal cytoplasm - thus lack differentiation to stratum spinosum.
Felis catus Papillomavirus type 2 and 4 are identified in these. Type 2 is the most prevalent.
Munday JS, Peters-Kennedy J. Consistent detection of Felis domesticus papillomavirus 2 DNA sequences within feline viral plaques. J Vet Diagn Invest 2010, 22: 946–949
Munday JS, French AF, Peters-Kennedy J, Orbel GMB, Gwynne K. Increased p16CDKN2A Protein Within Feline Cutaneous Viral Plaques, Bowenoid In Situ Carcinomas, and a Subset of Invasive Squamous Cell Carcinomas. Vet Pathol 2011;48:460-465.
Vascellari M, Mazzei M, Zanardello C, Melchiotti E, Albanese F, Forzan M, Croce MF, Alberti A, Abramo F. Felis catus Papillomavirus Types 1, 2, 3, 4, and 5 in Feline Bowenoid in Situ Carcinoma: An In Situ Hybridization Study. Vet Pathol. 2019;56:818-825.
Fibropapilloma – feline sarcoid
Feline Sarcoids (ACVP 2000)
176 bp from papilloma E2 gene – a highly conserved gene
19 of 23 positive
1 was tested and was BPV1 and BPV2 50% and 60% homology, and unrelated to other papillomaviruses
John S. Munday, Cameron G. Knight (2010) Amplification of feline sarcoid-associated papillomavirus DNA sequences from bovine skin Vet Derm 21 341-344
Feline sarcoids are uncommon dermal neoplasms that are thought to be caused by papillomaviral (PV) infection. Feline sarcoid-associated PV (FeSarPV) has been consistently detected in sarcoids from North American and New Zealand cats but has not been detected within any other feline sample. This suggests that feline sarcoids may develop due to cross-species infection by a PV from an unidentified reservoir host. While there is some epidemiological evidence to suggest that cattle are the reservoir host of FeSarPV, this PV has never been identified within any bovine sample. In this study both consensus PCR primers and primers specific to FeSarPV were used to investigate the presence of PV DNA within five fibropapillomas and 18 samples of inflammatory skin disease from cattle. Consensus primers amplified bovine PV-2 DNA from four fibropapillomas, but none of the dermatitis samples. However, specific primers amplified FeSarPV DNA from four fibropapillomas and five inflammatory skin lesions. To the best of our knowledge this is the first time that FeSarPV has been detected within any sample other than a feline sarcoid. The ability of FeSarPV to asymptomatically infect bovine skin suggests that cattle are the reservoir host of this PV and feline sarcoids could be the result of cross-species infection of a dead-end host by a bovine PV.
Squamous Cell Carcinoma
Subtypes
There are different types of squamous cell carcinoma.
- Conventional
- Well differentiated
- Poorly differentiated
- Acantholytic
- Clear cell
- Spindle cell squamous cell carcinoma
- Squamous cell arising in viral papillomavirus
Pathogenesis
Cats develop squamous cell carcinoma on their nasal planum and ears (auricle, pinna) expecially. Sunlight exposure is particularly involved. Cats prefer a temperature of 32 degrees C, and will seek out places to warm. Sunlight through a window is a good place. Some SCC contain papillomaviral DNA, which may alter prognosis.
Dos Santos et al (2023) reported on metastasis in 9 of 169 cases (5%). Most were on the nasal planum.
Munday JS, French AF, Gibson IR, Knight CG. The presence of p16CDKN2A protein immunostaining within feline nasal planum squamous cell carcinomas is associated with an increased survival time and the presence of papillomaviral DNA. Vet Pathol 2013;50: 269-273
Dos Santos A, Lamego ÉC, Eisenhardt LM, et al. Prevalence and anatomopathological characterization of cutaneous squamous cell carcinomas with regional and distant metastases in dogs and cats: 20 cases (1985-2020). Vet Comp Oncol. 2023; 21: 291-301.
Acantholytic squamous cell carcinoma
Spindle cell squamous cell carcinoma
Rodriguez et al (2021) reported on 18 cases in cats. 13 were on the pinna, 4 were periorbital, and one was on the muzzle. One metastasised to the local lymph node. SCSCC are dominated by spindle cells. There are often large individual or clusters of cells with large nuclei and large nucleoli. These will be cytokeratin positive, as will some of the spindle cells
Kogame T, Tanimura H, Nakamaru S, Makimura K, Okamoto H, Kiyohara T. Spindle cell squamous cell carcinoma arising in Bowen's disease: Case report and review of the published work. J Dermatol. 2017; 44: 1055-1058.
Rodríguez Guisado F, Suárez-Bonnet A, Ramírez GA. Cutaneous Spindle Cell Squamous Cell Carcinoma in Cats: Clinical, Histological, and Immunohistochemical Study. Vet Pathol 2021; 58: 503-507.