Vaccine-associated sarcoma in cat associated with the injection site, accounts for between 6 and 12% of feline tumors . It is a mesenchymal tumor in which the fibroblasts of the connective tissue proliferate. It is a very aggressive neoplasm with a great tendency to local recurrence. They appear as a small, rapidly growing lump or inflammation, however, they do not usually metastasize to other organs.

Vaccine-associated sarcoma in cat

Vaccine-associated sarcoma in cats Causes

In general, tumors appear as point genetic mutations. However, in the case of feline fibrosarcoma, it can cause these causes:

Vaccination : 

after a vaccination at the point of inoculation of the vaccine. Some cats develop a small inflammatory nodule at this point that disappears in about two to three weeks as a side effect of vaccination . If it does not go away, chronic inflammation can lead to the development of this tumor. This inflammation at the vaccine inoculation site occurs more frequently in vaccines with adjuvants, which are components that are added to vaccines to improve their effectiveness. The vaccines that most frequently contain adjuvants are those for rabies and feline leukemia.

Vaccine-associated sarcoma in cats Symptoms

Feline fibrosarcoma can appear at any age. However, it is more common in middle-aged cats . At first, the lump is very small and is noticeable when stroking the cat, but it increases in size very quickly .

This mass may be relatively mobile and attached to the subcutaneous tissue and underlying musculature, with probable infiltration of the surrounding structures. This makes the space between the tumor and healthy tissue poorly defined. The site of inoculation most often is the interscapular zone (between the shoulders and neck of the cat). Large masses can be injured or ulcerated.

Vaccine-associated sarcoma in cats Treatment

Fibrosarcoma treatment will depend on the size and location of the tumor and whether or not there is metastasis. In this way, the possible treatments would be:

Complete removal of the tumor : 

the main therapy will consist of the complete removal of the tumor, being convenient to remove all the muscles and fascia adjacent to the tumor, due to its great infiltrative capacity. Surgical margins of at least 2 cm are required, ideally 3-5 cm lateral and deep to the tumor mass, which may include the vertebral dorsal spinous processes and the dorsal edge of the scapula.