Cat Skin Cancer

Cat skin cancer was in the news today, March 18th 2011 (GMT). The story concerns an earless cat looking for a home. I think he will find one in the not too distant future because he is a complete charmer. His name is Winston. He lost his ears because of cancer. He was abandoned by his "owners" who moved and left him behind. Yes, it's one of those stories again. How can people do this? He had been living outside for five years through fierce sun and freezing cold (20 degrees Fahrenheit).

He is an all white cat and the exposure to the sun on his ears had caused the cancer. His ears were black (caused by the tumor) and his coat white. A very decent person, Marilyn Hendrickson, of the Kirkland’s MEOW Cat Rescue shelter took him to a vet who amputated his ears. He is now cancer free and looks a bit like a Scottish Fold (the cat breed with folded ears that lie flat to the head). He looks cute and is cute.

I can't publish his picture because I don't have permission but here is a picture of another cat, Lily, who lost her ears for the same reason:

Lily has no ears - photo Nana Wickström (Flickr)

It appears that the ears are particularly vulnerable as the covering of fur is very thin. White cats are even more vulnerable it seems. As I understand this is it because there is less pigment in their skin of the ear flaps. Skin pigmentation follows the fur pattern and colour. You can see this in Sphynx cats. Dark pigmented skin is underneath dark patches of fur. Winston should be a full-time indoor cat now or use a sheltered cat enclosure. And for that matter Sphynx cats should too! This probably also applies to the thin haired cats such as the Peterbald and Devon Rex.

Cats have higher rates of cancer than dogs probably because of the occurrence of FeLV. Cancer occurs more frequently in older cats (10-15 years of age).

Apparently skin tumors are common in cats, although many are not malignant. The incidence is high at 25 percent of all feline cancers.  The occurrence of cancer is based in both genetic and environmental factors.

Carcinogens are environmental factors that cause alterations to genes and chromosomes affecting cell growth.

Skin cancer can be caused by ultraviolet light (a carcinogen). This I presume was the cause of Lily's and Winston's ear flap (pinna) cancer. Ultraviolet light is invisible to us. It causes sunburn.

Cancerous cells are diagnosed through a biopsy (taking a sample and inspecting it microscopically).

Basal Cell Carcinoma

Most common type of cat skin cancer. Occurs in older cats and Siamese and domestic longhair cats. "Small nodular growths beneath the skin"¹. Can be a growth on the head, back and upper chest. They rarely become malignant (malignant means: "to become progressively worse"). In Persian cats they are more likely to become malignant, however. The treatment is to remove the cancer.

Squamous Cell Carcinoma

Called an "epidermoid (epidermal tissue) carcinoma (a malignant new growth)". Cauliflower appearance. More commonly occur around body openings and where there is "chronic skin irritation". Can spread. Can occur near base of tongue. Needs early detection and treatment.

Mast Cell Tumors

Usually under one inch long and found on "hind legs, scrotum and lower abdomen"¹. About 33% are malignant.

Melanomas

A malignant "neoplasm". Neoplasm means: An abnormal formation of tissue; for example, a tumor².

Pigmented spot enlarges and spreads, becomes raised and bleeds. Occur anywhere on the skin and in the mouth.

Uveal Melanomas

Eye tumors - slow growing. Eye pigment changes and possible pain and redness. Persian cats are predisposed to this form of cat skin cancer.

Cat Skin Cancer -- Note:

1. Cat Owner's Home Veterinary Handbook chapter 19

2. The Free Dictionary.




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