Feline Mast Cell Tumors

Mast cells are part of the innate immune system and are found throughout the body, particularly where tissues are close to the outside world such as the GI tract and skin. Feline mast cell tumours commonly arise in the skin (cutaneous form), the spleen or intestines (visceral form) but have also been reported in the mediastinum, nasal and oral cavity.

Mast cells are filled with granules which are released when the mast cell degranulates. The granules are made up of various substances including heparin, histamine and cytokines that attract other cells into the area to deal with the insult. Degranulation can be important in cats suffering from mast cell tumours as heparin can cause bruising around the tumour and histamine can cause vomiting and melena due to its effects on the GI tract. MCTs can go up and down in size quite rapidly because of degranulation and it can cause the lesion to appear erythrematous after handling. Histamine release can also cause hypotension and laboured breathing which is more likely to be seen with systemic disease. These signs also appear and disappear.

SPLENIC MAST CELL TUMOURS

Splenic MCTs are a very common cause of splenomegaly in the cat and MCTs are the most common splenic tumour. Up to a third of cases can develop ascites associated with it. The average age of cats with a splenic MCT is 10 years. Cats develop nonspecific signs associated with disease such as inappetance, vomiting, and weight loss 1 . Some cases of splenic MCT have been associated with sudden death or peritonitis associated with gastric ulceration due to histamine release 2 .   […]