Keynote Message

Mast cell tumours (MCT) are the most common skin cancer in dogs, and significant variability exists in their biological behaviour. Most of the tumours are cured with appropriate local therapy, but a subset shows malignant behaviour. This behaviour is evidenced by the potential to spread to lymph nodes, liver, spleen, and other areas and to thus become a systemic cancer. The variable behaviour makes it difficult to predict how an individual tumour is going to behave, and thus difficult to know what staging tests are needed, what treatments to offer, and what the prognosis will be in many cases. In addition to the controversies about systemic disease potential and prediction, opinions also vary over what treatment is needed to best attain local control of these tumours. In this session, findings of recent studies will be used to highlight what is known and what is still controversial in the diagnosis and treatment of mast cell tumours. Case examples will be used to illustrate the key points.

Key References

1.  Camus MS, Priest HL, Koehler JW, et al. Cytologic criteria for mast cell tumor grading in dogs with evaluation of clinical outcome. Veterinary Pathology. 2016;53:1117–1123. DOI:10.1177/0300985816638721.

2.  Garrett LD. Canine mast cell tumors: diagnosis, treatment, and prognosis. Veterinary Medicine: Research and Reports. 2014;5:49–58. DOI: 10.2147/VMRR.S41005.

3.  Hillman LA, Garrett LD, De Lorimier LP, et al. Biological behavior of oral and perioral mast cell tumors in dogs: 44 cases (1996–2006). Journal of the American Veterinary Medical Association. 2010;237:936–42. DOI:10.2460/javma.237.8.936.

4.  Stefanello D, Buracco P, Sabattini S, et al. Comparison of 2- and 3-category histologic grading systems for predicting the presence of metastasis at the time of initial evaluation in dogs with cutaneous mast cell tumors: 386 cases (2009–2014). Journal of the American Veterinary Medical Association. 2015;246:765–9. DOI:10.2460/javma.246.7.765.