Mast Cell Tumour Management (Case)

Question:

Beech is a golden retriever with a large ulcerated mass circumferentially affecting the skin of the anal region. Which of the following statements is not true?

A- diagnosis can be made by pathological assessment of cell (FNA) or tissue (incisional biopsy) specimens.

B-  In cases of mast cell neoplasia, it is inappropriate to commence therapy without knowledge of tumour grade.

C- Canine cutaneous mast cell tumours classically spread to the regional lymph nodes first.

D- Rapidly progressive ulcerated mast cell tumours are more likely to be high-grade than small non-ulcerated minimally progressive mast cell tumours.

E- Approximately 67% of canine cutaneous mast cell tumours in the pivotal trials for both masitinib and toceranib were shown to exhibit mutations in the c-kit gene.

Answer:

B is the wrong (correct) answer.

Decisions about therapy for canine cutaneous mast cells are made based upon many factors. Tumour grade is simply a proxy measure of the probable aggressiveness of a tumour; it is not the only such measure. Proof of metastasis, for example, is a more important finding than histological grade and would effectively render information about grade redundant.