Aside from adrenal disease and insulinoma, tumors of the skin are the most commonly seen neoplasms in ferrets. It doesn’t hurt that they are on the outside of the animal as well, so that attentive owners (and even some not-so-attentive ones) can readily alert their veterinarians.
Skin tumors, on the whole, are certainly not the worst thing for your ferret to develop — 95 percent are benign and simple excision is curative. Chemo- or radiation therapy is rarely performed, and unnecessary for a benign tumor.
The more common varieties of skin tumors may be diagnosed at home. They still need to be removed, but knowing what they are allows you to sleep better between the time you notice them and when you can get to the veterinarian’s office.
Sebaceous epitheliomas (also called basal cell tumors) are the most common type of skin tumor. These warty growths may attain a large size and become difficult to completely remove in one surgery, but you don’t have to worry about the tumor metastasizing and causing a life-threatening problem. Some large tumors die in the center due to an impaired blood flow, causing a cavitated appearance, and may be misdiagnosed as spider bites.
Mast cell tumors come in second overall. For more information on mast cell tumors, click here.
Apocrine tumors, arising from scent glands, are the third most common, and a small subset of these tumors are the “bad actors” of skin neoplasms. Apocrine scent glands are most common around the head, neck, prepuce, and vulva of ferrets — and it is not surprising that this is where most of the apocrine tumors appear. These tumors can be simple cysts (what happens when the duct to the surface gets blocked), benign neoplasms, or rarely, malignant ones. Apocrine cysts often resemble small hard BB’s under the skin, and may appear as dark round spheres of 1 to 2 millimeters in diameter when closely inspected. Benign apocrine tumors are large, freely movable lumps and are most common in the prepuce of male ferrets. Malignant apocrine tumors are seen almost exclusively in the prepuce or perivulvar area of females and grow quite rapidly. Unfortunately, these tumors tend to metastasize early and widely to internal lymph nodes and organs (the lung is a popular place) and surgical attempts at removal are usually initiated too late.
Other less common skin tumors include benign smooth muscle tumors of the muscles surrounding hair shafts (usually in the area of the neck or shoulder blades), and rarely, low-grade (non-metastasizing) malignancies associated with vaccination (though at a very low frequency and are certainly not a reason to forego your ferret’s shots).
All skin tumors should be removed. They often cause irritation for ferrets and will only grow, making surgery more difficult at a later time. But don’t panic when you see one — most often, they are only a minor nuisance.