ABSTRACT: Presented are the two most common feline tumours. The summarised information is an attempt to provide relevant epidemiology, histology and prognosis for feline skin tumours and lymphoma.

Veterinary professionals encounter patients on a daily basis that are – or potentially could be – suffering from cancer.

The forms that this disease takes are numerous – some being visually obvious, others being more elusive and subtle, thereby making cancer a feasible differential diagnosis for just about any medical case. The field is wide-reaching, the lists exhaustive.

This article sets out to concentrate on the two most prevalent feline tumours – namely lymphoma (accounting for up to 33% of malignant tumours) and the second most common tumour, that of the skin.

Skin tumours

Cats predominantly suffer from malignant tumours and the two types that prevail are soft tissue fibrosarcomas and squamous cell carcinomas (SCC) (Table 1).

Feline fibrosarcoma accounts for up to a quarter of skin tumours in this species. The lesions invade tissues locally and, although capable of metastasis, their potential for – and rate of – spread is low. Wide tumour-free surgical margins of two to three centimetres and ‘mop-up’ radiotherapy in awkward locations, are typical treatment options.

Vaccine-related, intrascapular ibrosarcomas are a complicated sub-group. Their behaviour warrants guidance from oncologists as intervention is challenging.1

Feline squamous cell carcinoma is the next most common feline tumour. Although not exclusive to unpigmented hairless skin, it does predominate in such areas. UV radiation causes DNA damage and these cell line mutations cause a slow, progressive de-differentiation from pre-cancerous change to SCC. Local lymph nodes and the lungs are often involved if spread occurs.

Surgical resection of the typically affected ear pinnae (Figure 1) or radiotherapy/ photodynamic therapy (PDT) of the nasal platum can be curative if the lesions are caught early (Figure 2a & 2b).

Figure 1: Excision of ear pinnae as consequence of SCC

Figure 2a: A SCC seen as a raised mass and ulceration on the nasal platum

Figure 2b: The SCC in the same patient after it had received photodynamic therapy


Feline lymphoma is the most common malignancy in cats, responsible for around 30 per cent of all feline tumours. Historically, approximately 70 per cent of cats with lymphoma would have tested positive for FELV. The affected cats were often young and had a high incidence of mediastinal thymic lymphoma. However, wide implementation of FELV vaccination has seen a reduction in this virus and, consequently, to retro-viral- associated lymphoma.

Lymphoma can also develop in FELV-free cats. Apparent breed susceptibility has been seen in young FELV-negative Siamese cats, which have an increased risk of developing mediastinal lymphoma.2

There is also a population of older cats that are free of FELV, but that show alimentary and nasal lymphomas. As such, lymphoma is complicated by its distribution across a range of ages, its possible relationship with FELV, and its varying organ associations – taking a mediastinal, alimentary or multi-centric form. Indeed, it may occur wherever lymphoid tissue exists, although rarely as a generalised lymphadenopathy (Figure 3).

Figure 3: A lymphoma presenting, uncharacteristically, as a focal lesion on the forehead of a Siamese cat.

Biopsy is the preferred method of diagnosis, and treatment is typically chemotherapy because of the systemic nature of the disease. Surgery for localised masses may be necessary. This approach can see patients go into long¬term remission.


These examples of companion animal cancer demonstrate that tumours can arise anywhere in the body, and with the exception of nerves, all tissue types are well represented – each giving rise to very common tumours.

Regardless of the tissue group, all the tumours represented have a more favourable outcome if they are identified in the initial stage of the disease. So early, definitive testing is a ‘must’ with regard to selection of the best and most appropriate treatment.

Treatment options are wide-ranging and, increasingly, available; but cost, however, will always remain a prohibitive factor. It is undoubtedly true that prevention is the better option; and although this statement may seem outlandishly optimistic, there are areas in which veterinary professionals can influence the incidence of some of the most common tumours: (i) by continuing to implement a vaccination protocol to eliminate retro-viral FELV and its causal links with feline lymphoma; and (ii) by endorsing the use and merits of complete sun block for susceptible animals to reduce the incidence of SCC.

Just as with human cancer, correct treatment is vital, understanding the epidemiology and influencing factors associated with progression of the carcinogenic process will permit intervention and manipulation of the disease at every available stage, especially avoidance of the carcinogens in the first instance. 


Rhian Williams BVM&S BSc MRCVS

Rhian qualified from the Royal (Dick) School of Veterinary Medicine, Edinburgh, in 1997 after gaining a Degree in Pathobiology (Hons 1st Class) from Reading University. She has remained in first-opinion practice since graduating and currently works at Vets on the Park in Cheltenham.

To cite this article use either

DOI: 10.1111/j.2045-0648.2011.00095.x or Veterinary Nursing Journal Vol 26 pp 352-354.


1.   MURPHY. S. (2006) Skin neoplasia in small animals 2, Common feline tumours. In Practice 28: 320-325.

2.   HAYES, A
. (2006) Feline lymphoma; principles of diagnosis and treatment. In Practice 28; 516-524.

Further reading

FRANKS, L. M. and TEICH, N. M. (1991) Introduction to the Cellular and Molecular Biology of Cancer Oxford University Press.

ETTINGER. S. J. and FELDMAN, E. C. (2000) Textbook of Veterinary Internal Medicine. Harcourt Brace.

Veterinary Nursing Journal • VOL 26 • October 2011 •