Feline injection site sarcomas

Abstract

Feline injection site sarcoma (FISS), formerly known as vaccine associated sarcoma (VAS), is a rare but life-threatening disease. The incidence estimates have varied from one case of FISS per 1000–10 000 cats vaccinated in North America and between one per 5000–12 500 vaccination visits in UK. It has been primarily associated with vaccine administration, but several other injectable materials/substances have been implicated as aetiologic agents, namely lufenuron, penicilin, metilprednisolone, meloxicam, non-absorbable suture material and microchip. FISS can have a long latency period (3 months to 13 years), but 8 years old is the average age of onset. FISS are tumours that arise subcutaneously, reaching a variable number of layers beneath the skin (muscle, bone). They are firm, not painful, solid and variable in size. Clinical assessment and biopsy are the basis for FISS diagnosis. In order to prevent FISS, vaccination should be carefully planned and be provided in easily resectable regions. Hind legs, tail and flanks, are preferable regions for vaccine administration.