It is quite common to find unusual lumps and bumps on any area of the ferret's body, particularly as they age. This paper will help you decide what is the most likely problem and what action to take. *Note: I will not be discussing any skin diseases such as fleas, mites or skin infections that do not cause an actual raised lump or mass.

Types Of Skin Masses

Abscesses
Abscesses are localized areas of inflammation that can occur anywhere in or on the body. Abscesses are most commonly created by bacteria but they can also be caused by fungi or noninfectious irritants and be sterile. Abscesses can form after punctures or tears, as with bites, or as a result of an infection in a specific tissue such as a tooth or anal gland. Multiple small abscesses can form internally when an infectious agent travels through the blood and then lodges in various tissues such as the liver, kidney or lungs. Fortunately, abscesses are uncommon in ferrets in the United States and are most often associated with infected anal glands, infected teeth, or the prostate gland. Abscesses are rarely seen post surgically if standard sterile technique is used.

Abscesses in the skin can appear quickly and may be firm and painful when touched. An abscess is surrounded by a reddened and inflamed area and feels warm to the touch. In my experience, most abscesses in ferret skin do not readily rupture as opposed to what is observed in humans, dogs or cats. This may be due to the thickness of ferret skin or the ability of the body to effectively keep the infection walled off. An abscess in the skin that does not involve any deep tissues will move with the skin. A swelling will appear on either side of the anus in the case of anal gland abscesses. The stools can become thin and ribbon-like due to pressure by the large abscess on the rectal wall. Dental abscesses are usually associated with either a canine tooth or an upper molar. Dental abscesses appear as hard lumps either on the lower jaw, usually near the chin, or on the upper jaw, often under or just in front of the eye. Abscesses should be treated as soon as possible. Besides being painful, there is a potential that an abscess can spread into deeper tissues allowing the bacteria to enter the blood stream. This could lead to a condition known as septicemia where the infectious organism is circulating throughout the body via the blood. Septicemia can lead to internal abscess formation or an overwhelming infection and death.

Cysts
A cyst is a closed sac in or under the skin that is lined with epithelium, which arecells bound together by connective material, and contain fluid or semisolid material. Cysts are usually round, firm to the touch and moveable with the skin. Cysts, unlike abscesses, do not have red, inflamed skin surrounding them and are not usually painful. Cysts are rare in the ferret but can be found most often in the male around the opening of the prepuce where they appear as small bluish blister-like lumps. However, skin cancer can also occur in this area and it is important to differentiate between the two. A cyst can occasionally form after a vaccination. This is an inflammatory response to chemicals that the vaccine contains and may appear up to one month after the vaccination and take six months or longer to disappear. Cysts are not dangerous, and are usually painless. However, they can increase in size and eventually become uncomfortable. It is best to have cysts removed while they are still small.

Sialocele
A sialocele is an accumulation of saliva under the skin of the lower jaw or neck. The saliva leaks out of a salivary duct damaged by either trauma or other disease, and forms a pocket under the skin. Sialoceles are painless and soft and fluctuant to the touch. They usually do not move with the skin. Sialoceles are not life threatening, but should be treated surgically because they rarely disappear on their own and can become quite large.

Parasitic
The larvae of the fly species Cuterebra can burrow into the skin and create a lump. This occurs most frequently in young ferrets kept outdoors. The adult fly lays one egg on the skin of the host. The site chosen is often the neck or upper back. The egg hatches and the larva burrows into the skin where it will grow until it reaches the pupa stage. The larva can become quite large, causing a lump about the size of a nickel. The lump has a small breathing hole and the head of the larva can be seen moving inside this opening. The lump moves with the skin. Once the larva reaches the pupa stage, it will leave the ferret's skin through the breathing hole, drop to the ground, form a pupa and eventually metamorphose into an adult fly. It is best to have the larva removed surgically because if it ruptures the ferret can experience a serious allergic reaction.

Lymph Nodes
Lymph nodes can be enlarged in the ferret for a number of reasons, most notably lymphosarcoma, which is a type of cancer, and lymphoid hyperplasia, which is where lymph nodes are “overreacting” to some stimulus. Lymph nodes are found all over the body, but are most easily felt in the neck at the angle of the jaw, just in front of the shoulders, in the armpits, in the groin and along the back of the thighs. Enlarged lymph nodes do no move with the skin because they are connected to deeper tissues, but they can be felt just under the skin. Enlarged lymph nodes should be investigated as soon as possible so appropriate action can be taken. Enlarged lymph nodes are a common finding in ferrets of all ages.

Neoplasia (Cancer)
Neoplasia is the most common cause of skin masses in the ferret. Ferrets can develop a wide variety of skin cancers including mastocytomas, histiocyotomas, sebaceous gland adenomas and adenocarcinomas, basal cell tumors, lymphoma, leiomyomas, lipomas, fibromas, fibrosarcomas and hemangiomas to name a few. The name of the tumor is based on the type of tissue that is cancerous. Fortunately the majority of skin tumors in ferrets are benign, meaning they only spread locally and not to internal organs. However, there are a few tumors that can be highly malignant and can spreading quickly, so we recommend all skin tumors be removed without delay and be identified by a pathologist. If the tumor involves only the skin, it will be moveable. Some tumors involve deeper tissue such as fibromas and fibrosarcomas or the tumors on the tail tip called chordomas, and will not be freely moveable. Most skin tumors are small, painless lumps, but some may become itchy, ulcerated, painful or quite large over time.

Diagnosis

If your ferret develops a skin lump you should seek veterinary attention as soon as possible. The first part of the diagnostic process is the physical examination. Some masses are readily identifiable during the examination and treatment may be prescribed without further diagnostics. If the diagnosis is unclear, your veterinarian may biopsy the mass with a needle. Biopsies are often done while the animal is awake because the procedure is quick and relatively painless. If a larger or deeper sample is needed it may be necessary to use a local or general anesthetic. The biopsy sample is examined under the microscope either in your veterinarian's office or is sent to a veterinary pathologist. Abscesses and sialoceles can often be diagnosed immediately based on the material extracted from the lump. A microscopic examination of the biopsy sample will be necessary to differentiate types or presence of cancer. Additionally, an x-ray may be recommended if an abscess is present, especially of the teeth, or if a malignant tumor is suspected. For all suspected malignant tumors, an x-ray of the chest should be performed to determine if the tumor has spread. A complete blood cell count and/or serum biochemistry might be performed in the case of abscesses, enlarged lymph nodes and tumors to detect abnormalities in other organs and the immune system. These blood tests may also be performed to determine if your pet is in good enough health to undergo surgery if it is the recommended treatment.

Treatment

The recommended treatment for most skin masses in the ferret is complete surgical removal. In the case of abscesses, it may be advantageous to put the ferret on oral antibiotics first and then surgically remove the abscess along with its thickened wall after some of the swelling has subsided. The source of the abscess should be removed such as an infected tooth or an infected anal gland. Cysts should be removed if they are persistent or become enlarged. Sialoceles are treated by draining the pocket of saliva and then keeping the area open until it heals. As discussed, Cuterebra larva must be removed surgically, usually under a local or general anesthetic. If multiple lymph nodes are enlarged, it is necessary to remove at least one to determine the cause and future treatment.

In my opinion, all skin tumors on ferrets should be removed as soon as possible because of the potential for malignancy. Since most ferrets are excellent surgical candidates with the proper anesthesia, I often do not biopsy a tumor presurgically, but rather remove it entirely and then have it examined by a pathologist postoperatively. It is important to have a pathologist make a diagnosis on a surgically removed mass to determine if future treatment is necessary. Although the prognosis for aggressive, malignant tumors is guarded to grave, some ferrets benefit from chemo or other therapy postsurgically. It is my opinion that one should never adopt a “wait and see attitude” in ferrets with skin tumors. It is much easier to prevent localized disease with early removal than deal with systemic problems because you waited too long.

Skin masses are usually removed under a general anesthesia. Either conventional surgical techniques are employed or electrosurgery. Unless the lump was an abscess, or the surgical site was grossly contaminated, it should be unnecessary to use antibiotics postsurgically. Sutures or staples may be placed in the skin or absorbable sutures may be hidden under the skin. Ferrets rarely chew out their stitches, but you should examine the surgical site at least twice a day for any drainage, swelling or loss of sutures. If the surgical site was large or very deep, the ferret will benefit from the use of analgesics for a few days postoperatively.

So…as you can see, this need not be a complex issue. If you find a lump, get it attended to now, not later. Be prepared that often the best course of action is surgical removal. Your ferret will thank for your prompt action!