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Also know as: '''''vaccine site-associated sarcoma — injection-site sarcoma — vaccine-induced sarcoma'''''

Also know as: '''''Vaccine Site-Associated Sarcoma — Injection-Site Sarcoma — Vaccine-Induced Sarcoma'''''

==Introduction==

==Introduction==

The incidence of vaccine-associated sarcomas is difficult to estimate, however figures of '''1 in 1000 to 1 in 10,000 vaccines''' administered have been reported.

The incidence of vaccine-associated sarcomas is difficult to estimate, however figures of '''1 in 1000 to 1 in 10,000 vaccines''' administered have been reported.

The vaccines most often implicated in tumour development are the '''FeLV and the Rabies''' vaccines. The likelihood of sarcoma development increases with the number of vaccines administered in one anatomical location. Most tumours arise '''within a few months''', however the process may take years in some cats.

The vaccines most often implicated in tumour development are the '''[[FeLV]] and the [[Rabies]]''' vaccines. The likelihood of sarcoma development increases with the number of vaccines administered in one anatomical location. Most tumours arise '''within a few months''', however the process may take years in some cats.

The pathogenesis of the disease is thought to be that the localised inflammatory response elicited by certain vaccines may lead to '''uncontrolled fibroblast and myofibroblast proliferation''' in susceptible cats. This later evolves into an aggressive tumour.

The pathogenesis of the disease is thought to be that the localised inflammatory response elicited by certain vaccines may lead to '''uncontrolled fibroblast and myofibroblast proliferation''' in susceptible cats. This later evolves into an aggressive tumour.

The role of '''adjuvants''' in the development of the tumour has been the subject of much speculation, and aluminium, which is commonly used in adjuvants, has been found in vaccine-induced fibrosarcomas. However there have been no significant differences found between the incidence of tumours using adjuvanted or non-adjuvanted vaccines.

The role of '''adjuvants''' in the development of the tumour has been the subject of much speculation, and aluminium, which is commonly used in adjuvants, has been found in vaccine-induced fibrosarcomas. However there have been no significant differences found between the incidence of tumours using adjuvanted or non-adjuvanted vaccines.

==Clinical signs==

==Clinical Signs==

The most notable clinical finding is a '''swelling''' which appears at the site of a previous vaccination or injection, usually in the interscapular space, but sometimes on the hindlimb, flank or over the scapula. This rarely occurs sooner than '''2-3 months''' after the vaccine. The swelling then develops into a '''hard, non-painful mass''' and slowly becomes less mobile as it '''attaches''' to the underlying muscle and bone.

The most notable clinical finding is a '''swelling''' which appears at the site of a previous vaccination or injection, usually in the interscapular space, but sometimes on the hindlimb, flank or over the scapula. This rarely occurs sooner than '''2-3 months''' after the vaccine. The swelling then develops into a '''hard, non-painful mass''' and slowly becomes less mobile as it '''attaches''' to the underlying muscle and bone.

==Prevention==

==Prevention==

Some '''recommendations''' for preventing or reducing the incidence of vaccine-associated tumours include:  

Some '''recommendations''' for preventing or reducing the incidence of vaccine-associated tumours include:  

 

:Changing the vaccination site location

Changing the vaccination site location

:Not giving vaccinations intra-muscularly - subcutaneous tumours will be noticed sooner

 

:Not vaccinating a cat with a history of vaccine-associated sarcomas

Not giving vaccinations intra-muscularly: subcutaneous tumours will be noticed sooner

:Giving rabies and FeLV vaccinations in the '''distal hindlimbs'''

 

:Keeping accurate '''records''' of the site of vaccine administration, the vaccine serial and lot number.

Not vaccinating a cat with a history of vaccine-associated sarcomas.

 

Giving rabies and FeLV vaccinations in the '''distal hindlimbs'''

 

Keeping accurate '''records''' of the site of vaccine administration, the vaccine serial and lot number.

However these recommendations are controversial and do not prevent the disease but rather '''enable an earlier diagnosis''' and a higher surgical cure rate.

However these recommendations are controversial and do not prevent the disease but rather '''enable an earlier diagnosis''' and a higher surgical cure rate.

[[Category:To Do - Helen]]

[[Category:To Do - Review]]

[[Category:Neoplasia]]

[[Category:Expert Review - Small Animal]]