Feline Fibrosarcoma

Tuxedo cat

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Tuxedo cat (healthy but may be suffering a mild form of Feline Hyperesthesia)- see below for rights

Feline Fibrosarcoma are highly malignant, highly aggressive, tumors. The word “sacrcoma” means cancer of the supportive or connective tissue. Just below the dermis of the skin is the epidermis. The epidermis is made up of connective tissue. See the drawing:

Skin Layers

Above: The layers of skin showing the epidermis, dermis and subcutis. See rights to publish this picture

Feline Fibrosarcoma occurs in the skin and is the sarcoma most commonly associated with vaccines. It is a vaccine associated sarcoma (VAS). VAS has resulted in new cat vaccine recommendations. The cancerous growth can be large when first noticed and also be infected and/or ulcerated. It may

It has been found that inflammation of the subcutis (see drawing above) precedes the cancer and inflammation occurs more often when the vaccine contains a substance called an adjuvant (a substance that catalyzes or modifies the action of the vaccine). A new rabies vaccine has been brougth out I understand as a result with less incidents of inflammation.

Feline Fibrosarcoma (not necessarily occuring as a result of a vaccination) can invade the bone and cause lameness by the destruction of the medulla and cortex. The medulla ossea is the bone marrow in the hollow part of the bone. The cortex is the outer shell of the bone.

The prognosis is described as “guarded to poor” (src: http://priory.com). In other words not too good. This source also says that the tumor free period after treatments which includes surgery to remove the tumor, chemotherapy and radiotherapy if appropriate and repeat surgery is no more that 5 months and surival for the cat no longer than 16 months.

The Wikipedia author says that the period before recurrence of the tumor after surgery depended on the extent of the surgery. The more extensive the greater the success in terms of time free of the tumor. For extensive surgery the time was an average of 325 days and for less extensive surgery it was 79 days. It would seem to be a trade off as extensive surgery could have deliterous consequences for the cat that outweigh the benefits. Either way the time free of the cancer after surgery seems short to me. This would beg the question, “Is it worth it?” I don’t have the answer, the veterinariain should.

A factor in deciding surgery will no doubt be whether the disease has spread (called metastasis). Apparently one in five or 20% of cats with Feline Fibrosarcoma suffer the consequences of the cancer speading usually to the lungs, and/or lymph nodes or skin.

A combination of surgery and intradermal LPSp (lipopolysaccharideand oral cyclophosphamide was referred to on this web page. Cyclophosphamide is a chemotherapy drug given to humans to combat cancer. It is not clear if this treatment (carried out some time ago I suspect) was adopted or had improved chances of success.

From Feline Fibrosarcoma to Cat Health Problems


  1. Wikipedia
  2. Veterinary Notes For Cat Owners by Dr Trevor Turner and Jean Turner VN
  3. www.medcyclopaedia.com (definition)
  4. http://priory.com/vet/feline.htm
  5. www.cancerbackup.org.uk


Photograph of layers of skin: this is published under a Wikipedia commons license and is in the public domain in the USA. If it is a problem to someone please tell me and I’ll deal with it promptly. Thanks.

Photo of Tuxedo cat – you are free to use this photo provided it is not hot linked (i.e. please down load and then upload to your server). Also I’d appreciate a link to this page.

11 thoughts on “Feline Fibrosarcoma”

  1. Thanks, Tania, for your input. Appreciated. I had to link to your photo to avoid upsetting advertisers, sorry. Just click on the link and visitors can see it if they wish.


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