Finding a lump or bump on your dog is likely to trigger a wave of fear and anxiety, especially if it suddenly sprouts out of nowhere. More often than not, our minds immediately jump to the worst scenario: my dog has cancer.
Fortunately, less than half of lumps on dogs are malignant, or cancerous, and most are treatable. In fact, lumps on or below the skin are the most common masses reported in dogs, representing roughly one third of all tumors.
Most lumps on dogs look or feel similar regardless of whether or not they are cancerous, so it’s crucial to have it checked by your veterinarian to know for sure. While a quick Google search may be tempting, it’s easy to misdiagnose your pet’s lump and subsequently delay the care they actually need. Early intervention can prevent unnecessary discomfort and potentially save them from serious, life-threatening consequences.
Let’s explore some of the lumps and bumps that are common on dogs, their characteristics, and what they mean for a dog’s overall health and longevity.
First Thing First: Don’t Panic
Lumps and bumps pop up on dogs for a variety of reasons, many of which are of little threat to your dog’s life. The bump could be an abscess secondary to a bug bite, an inflamed hair follicle, a benign (non-cancerous) fatty growth, or a more serious condition, like cancer.
Finding a lump on a dog does not necessarily mean the worst, but it is important for a veterinarian to evaluate it to ensure a proper diagnosis is obtained and a treatment plan is initiated if necessary.
In most cases, it is appropriate to schedule an appointment that is convenient for you, such as your next day off work. However, if the lump or bump is hot to touch, growing quickly, producing pus or discharge, actively bleeding, or if your dog is in pain, you should take your dog to an emergency veterinary hospital for more urgent care.
Types of Lumps on Dogs
Hard, immovable lumps on dogs, or sudden lumps on dogs tend to be more worrisome than soft, moveable lumps on dogs or slow-growing lumps on dogs, but that’s not always the case, as many different types of lumps can appear to be similar.
Lumps on dogs can occur either on the skin surface, referred to as cutaneous, or beneath it, referred to as subcutaneous.
Common cutaneous masses, or lumps on the skin of dogs include:
Mast Cell Tumors
Mast cell tumors are the most common malignant, or cancerous, lumps found on dogs. This type of dog skin cancer is usually on the surface of the skin, but can be below the skin, or subcutaneous, as well.
These masses are usually red, raised, firm, and often form a wound that will not heal. A hard, bleeding lump on a dog’s skin is a typical appearance of a mast cell tumor, although they can vary greatly.
This cancerous lump on dog skin tends to be aggressive and spread quickly, so it’s important to have it surgically removed as soon as it is diagnosed. Complete surgical removal is curative as long as the cancer has not yet spread to other parts of the body. In some cases, follow up radiation therapy or chemotherapy may be needed.
Histiocytomas are benign (non harmful) skin growths that usually occur in young dogs less than a year of age, although they have been reported in dogs up to 6 years old. Histiocytomas are red, raised, hairless, button-like growths, typically the diameter of a nickel or quarter, and commonly occur on the head or limbs.
Since this red lump on dog skin can appear similar to a mast cell tumor, you should have it tested by your veterinarian to be certain. Histiocytomas typically regress on their own without any treatment.
Perianal Gland Adenoma
Perianal gland adenomas are common skin tumors of dogs that arise from the glands around the hairless skin of the anus. These are slow growing, benign lumps that occur mostly in intact (non-neutered) male dogs, although they have been reported in spayed females as well.
While these lumps do not spread to other parts of the body, they are locally invasive, meaning they disrupt surrounding tissues, and are prone to infection. So they should not be ignored. The treatment of choice in intact male dogs is castration and tumor removal. Small tumors frequently regress after neutering, and may not require surgical removal. Treated pets typically go on to live long, healthy lives.
Sebaceous Gland Adenomas
Sebaceous gland adenomas, also called sebaceous cysts, are non-cancerous growths that protrude from the surface of the skin. These are usually hairless, firm, small lumps on dogs that occur mostly on the head, neck, back, eyelids, and limbs. These dog cysts can burst open, become irritated, infected, or a combination thereof, but usually they are not problematic.
Removal may be recommended if sebaceous gland adenomas are troublesome to the dog, however in most cases, no treatment is necessary.
Melanomas are tumors of melanocytes, the cells that produce pigment in animal skin. A melanoma is usually a black lump on a dog, but they are sometimes red. These are hard, immovable lumps on dogs. Melanomas most often occur in the oral cavity or on the toes, but these lumps can be found on haired skin as well.
While melanomas on haired skin are usually benign, melanomas found in the mouth or on the toes are usually cancerous tumors in dogs. Malignant melanomas are very aggressive, and quickly spread to other parts of the body. Surgery is necessary for treatment of melanomas. Some cases will require chemotherapy or radiation therapy in addition to surgery. The sooner a melanoma is identified and treated, the better the dog’s chances of survival will be.
Squamous Cell Carcinomas
Squamous cell carcinomas are a common cancerous growth of skin cells in dogs. These lumps can occur anywhere on a dog’s body, such as the abdomen, thorax, legs, toes, paw pads, ears, mouth, or nose. Frequent exposure to UV light is a known cause for developing this type of dog skin cancer, therefore, it is more often seen in dog’s with light coats or parts of the dog with little coat coverage, like the belly.
Squamous cell carcinomas can appear many different ways. The usual appearance is a single red lump on a dog’s skin. Sometimes they develop as a small area of irritated, red, or ulcerated skin, while other times, they develop as plaques or crusts on a dog’s skin. Carcinomas of the toe or nail bed tend to be red, irritated, and ulcerated, and are usually quite painful. Dogs may even lose nails on the affected toes.
Treatment of squamous cell carcinomas in dogs is surgery, especially if it is affecting the toe, as it tends to be more likely to spread from that location. If the lump is removed before it spreads, dogs have a great prognosis and chance of survival.
Warts, or papillomas, are benign lumps on dog skin that are caused by Canine Papilloma Viruses. Dog warts are usually small and light-colored with a rough, jagged appearance. These lumps are mostly found in or around the mouth, on the feet, or on the eyelids, but they can grow anywhere on the body. Young dogs less than 2 years old are the most commonly affected.
Dog warts often disappear spontaneously as the dog develops immunity against it. However, some warts may need to be surgically removed if they become irritated, infected, cause pain, or fail to regress on their own.
Hives in dogs are similar to hives in humans. They appear suddenly as red, raised, circular bumps on the surface of the skin, and can occur anywhere on a dog’s body, including in their mouth. Hives in dogs can vary from a few millimeters to several centimeters in size. If hives become large enough, they can blend together, or coalesce.
Hives are caused by direct contact with an allergic substance such as an insect bite, food, pollen, mold, vaccinations, or medications. Typically, hives are self-limiting and resolve after removal of the allergic substance. Nevertheless, allergic reactions can be severe, and potentially life threatening, so your veterinarian should be notified immediately if you notice hives on your dog.
Common subcutaneous masses, or lumps below the skin of dogs include:
Lipomas, tumors of fatty tissue, are the most common benign tumor of dogs. These fatty lumps on dogs feel soft, or squishy, and are usually freely moveable beneath the skin, meaning that they are not fixed in place or attached to underlying tissues. Fatty tumors in dogs commonly appear on the chest or abdomen, but can occur anywhere on the body. Some lipomas will hardly grow after initially developing, while others seem to grow relatively quickly.
Although lipomas are non-cancerous, they can still be problematic if they develop in places that impair a dog’s ability to walk or lie down. If a lipoma is growing quickly or in a worrisome location, surgical removal is typically recommended.
Abscesses in dogs are pockets of pus underneath the skin. These are usually soft lumps on dogs that are warm to touch and painful, and occur secondary to a bite wound or skin injury. Abscesses in dogs are often just below the skin, can be large or small, and sometimes rupture and drain a foul smelling fluid. They can occur anywhere on the body. Abscesses are also seen on the muzzle of dogs, usually underneath the eye, secondary to dental disease.
Dogs with abscesses will need veterinary care to have the abscess drained and flushed out. Antibiotic therapy as well as pain medications are needed. Abscesses in dogs are usually so painful that many pets will need some level of sedation in order for the veterinarian to treat it properly and spare your dog from additional pain or discomfort.
Soft Tissue Sarcomas
Soft tissue sarcomas are a category of cancerous tumors, particularly those arising from the connective muscle or nervous tissues in dogs. Since these tissues are present throughout the entire body, these tumors can develop anywhere. Most often they are seen on the legs, chest, or abdomen of affected dogs, and are more common in middle aged to older dogs.
Soft tissue sarcomas are typically hard, immovable lumps on dogs found beneath healthy skin. These cancerous tumors in dogs often do not spread, but will grow into and disrupt surrounding tissues.
Surgical excision is the best treatment for soft tissue sarcomas in dogs. The surgeon must take wide margins to avoid leaving any of the cancer cells behind, so it is ideal to remove these tumors while they are still small. In some cases, followup chemotherapy or radiation therapy may be needed. After successful surgical removal, most dogs will live full life spans.
Peripheral Nerve Sheath Tumors
Peripheral nerve sheath tumors are lumps that grow from the nerve cells in dogs, and can occur anywhere in a dog’s body. They can be felt as hard, immovable lumps on dogs underneath the skin when they grow close to the surface. These lumps are usually not painful when touched, but some dogs will bite or chew at them due to nerve irritation.
Peripheral nerve sheath tumors do not commonly spread, but are locally invasive. Treatment of choice is surgical removal of the tumor, although recurrence is common. In some cases, amputation of affected limbs and/or radiation therapy are necessary. Unfortunately, most dogs with peripheral nerve sheath tumors may only live up to one year despite appropriate treatment.
Enlarged Lymph Node
Lymph node enlargement in dogs occurs for many reasons such as infection, inflammation, or cancer. Enlarged lymph nodes are firm, moveable lumps felt underneath healthy skin of dogs. They are usually detected under the chin, on the neck, the front of the shoulder, or the back of the rear leg. Enlargement of a single lymph node is not as worrisome as enlargement of multiple lymph nodes, which is often indicative of systemic disease or cancer.
Treatment of lymph node enlargement in dogs depends on the underlying cause. Various medications, chemotherapy, or even surgery may be recommended based on the cause of the lymph node enlargement. Depending on the cause the long-term prognosis can vary considerably.
Diagnosing Lumps on Dogs
As previously mentioned, any new lumps or bumps on your dog should be evaluated by your veterinarian. A thorough physical exam can help your veterinarian narrow down a list of possible diagnoses. Additionally, providing your veterinarian with a detailed history of your pet can be helpful.
Let your veterinarian know whether the lump developed suddenly, if you’ve noticed any changes in your dog’s behavior, and whether or not the lump has grown or changed since you first noticed it.
Many different types of lumps and bumps on dogs can appear and feel similar, so testing the lump to determine exactly what it is and whether or not it could be potentially problematic for your pet is always advised. Bloodwork and/or imaging, such as radiographs (X-rays), may also be recommended based on your dog’s specific case.
The first recommended test is usually a fine needle aspirate and cytology. This is a quick, non-invasive, and affordable test in which your veterinarian will use a needle to suck out, or aspirate, cells from the lump to determine their origin and behavior. The cells are then smeared on a glass slide, stained, and evaluated under the microscope.
In some cases a biopsy will be recommended. This is a more invasive procedure in which your veterinarian will take a small chunk of tissue from the lump and send it to a pathologist. Your dog will likely require some form of sedation for this procedure, but can usually return home the same day. Biopsy samples are almost always diagnostic and can tell you exactly what is causing your pet’s lump and what treatment options are available.
Treating Lumps on Dogs
After the lump is tested and a diagnosis is confirmed, your veterinarian will guide you through treatment options, if necessary. As discussed, treatment can vary greatly depending on the type of lump your dog has.
As previously mentioned, some common forms of treatment for lumps on dogs include:
- Surgical removal
- Draining (for abscesses)
- Topical ointments (for skin conditions like hives)
- Chemotherapy (if cancerous)
- Radiation (if cancerous)
Even when a lump is diagnosed as cancerous or malignant, your dog may have a great outcome, especially if treatment is initiated early and aggressively.
The cost of treatment for lumps on dogs varies based on the diagnosis. However, treatment will always be more affordable if the lump is properly addressed and cared for earlier, while it is smaller and less likely to have caused secondary issues, like infection, that will also need to be treated.
Remember, a lump cannot be treated until it is identified by you, the responsible pet parent. Check your pet frequently for new lumps or bumps so you can more quickly spot any abnormal growths on your dog and have them tested and treated earlier rather than later.
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