
A hard immovable lump on your dog's leg can be a worrying sight. It's a common concern for many dog owners, and it's essential to understand what could be causing it.
The lump could be a result of a fatty tumor, also known as a lipoma. These are common in dogs and can appear as a hard, immovable lump under the skin.
Swollen lymph nodes can also cause a hard lump on your dog's leg. This is often a sign of infection or inflammation in the body.
In some cases, a hard lump on your dog's leg can be a sign of a more serious underlying condition, such as cancer.
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Causes and Types of Dog Tumors
Dog tumors can be caused by a variety of factors, including diet, genetics, and environmental chemicals. Genetics play a significant role, with some breeds being more prone to certain types of tumors.
Lipomas, a type of fatty tumor, are common in dogs and can occur due to diet, genetics, or other factors. Maintaining a healthy weight may help prevent lipomas.
Some common causes of lumps on dog legs include mast cell tumors, lipomas, and soft tissue sarcomas. Mast cell tumors are usually red, raised, and firm, and can be aggressive and spread quickly.
Here are some common types of dog tumors:
Each type of tumor requires a different treatment approach, so it's essential to have your dog examined by a veterinarian to determine the cause and type of tumor.
Causes of Fatty Tumors in Dogs
Lipomas in dogs are thought to occur due to a number of factors.
Diet plays a role in the development of fatty tumors in dogs. Maintaining your dog's weight at a healthy level may help to prevent lipomas from occurring.
Genetics can also contribute to the occurrence of lipomas in dogs.
Chemicals in the environment and drug interactions are other potential causes of lipomas in dogs.
While it may not be possible for your vet to determine the exact cause of your dog's lipoma, taking steps to prevent obesity and maintaining a healthy lifestyle can help reduce the risk of fatty tumors.
A table of potential causes of lipomas in dogs would look like this:
Soft Tissue Sarcomas
Soft tissue sarcomas are a type of cancerous tumor that can develop anywhere in a dog's body, but are most often found on the legs, chest, or abdomen.
These tumors are typically hard, immovable lumps that appear beneath healthy skin, and in most cases, do not spread to other areas of the body.
However, it's essential to have soft tissue sarcomas diagnosed and treated promptly, as they can grow into and disrupt surrounding tissues.
Surgical excision is the best treatment for soft tissue sarcomas, and it's ideal to remove these tumors while they are still small to avoid leaving any cancer cells behind.
In some cases, follow-up chemotherapy or radiation therapy may be needed after surgical removal.
Most dogs that undergo successful surgical removal of soft tissue sarcomas can live full life spans.
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Causes of Dog Lameness
Dog lameness can be caused by a variety of factors, including lipomas that grow near joints, making it uncomfortable for your dog to move.
Lipomas are a common type of tumor in dogs that can cause lameness if they grow near joints. If your dog's lipoma is in an uncomfortable location, your vet may recommend surgery to remove it.
In some cases, lipomas can grow quickly and surround nearby tissues, leading to discomfort for your pup. This is known as an infiltrative lipoma, and it can be more challenging to remove than a regular lipoma.
The location of the lipoma is not the only factor that can cause lameness in dogs. Other types of lumps and bumps on dog legs can also cause discomfort and pain, making it difficult for your dog to walk or run.
It's essential to have any new lumps or bumps on your dog evaluated by your veterinarian to determine the cause of lameness. A thorough physical exam can help your veterinarian narrow down a list of possible diagnoses.
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Under the Skin Types
Lipomas, also known as fatty tumors, are the most common type of lump found under a dog's skin. They're usually small, hemispherical, and can be felt just under the skin.
Lipomas are often soft to the touch and can be moved a little, although firmer, stationary lipomas are also fairly common. Your vet will perform a fine needle aspiration to suction out a sample of cells, which will be examined under a microscope by a veterinary pathologist.
Other types of lumps that can appear under a dog's skin include mast cell tumors and soft tissue sarcomas. Mast cell tumors are often hard, immovable lumps found beneath healthy skin, and can be cancerous. Soft tissue sarcomas are a category of cancerous tumors that can develop anywhere on a dog's body, and are more common in middle-aged to older dogs.
Here are some key characteristics of common lumps found under a dog's skin:
It's essential to have any new lumps or bumps on your dog evaluated by your veterinarian as soon as possible. A thorough physical exam, along with a detailed history of your pet's condition, can help your veterinarian narrow down a list of possible diagnoses.
Symptoms and Diagnosis
If you've noticed a hard, immovable lump on your dog's leg, it's essential to have it evaluated by your veterinarian as soon as possible.
A thorough physical exam can help your veterinarian narrow down a list of possible diagnoses, and providing a detailed history of your pet's development, behavior, and any changes in the lump can be helpful.
Your veterinarian will likely recommend a fine needle aspirate and cytology, a quick, non-invasive, and affordable test that involves using a needle to suck out cells from the lump to determine their origin and behavior.
In some cases, a biopsy may be recommended, which involves taking a small chunk of tissue from the lump and sending it to a pathologist for evaluation.
If your dog's lump feels soft and can be moved a little, it might be a lipoma, but it's always best to have it examined by a veterinarian to determine the exact cause.
A fine needle aspiration will be able to immediately identify a lipoma or cyst, and an excisional biopsy is not usually recommended without analysis unless the vet is certain the lump is benign.
The single greatest influence on a successful outcome is how quickly you choose to get a lump checked, especially in areas with poor skin coverage like the head, legs, and tail.
Here are some possible next steps for your veterinarian:
- Fine needle aspiration and cytology
- Biopsy
- Imaging, such as radiographs (X-rays)
- Bloodwork
Remember, early detection and treatment are essential for good treatment outcomes, so don't hesitate to schedule an appointment with your veterinarian as soon as possible.
Treatment and Prevention
Treatment and prevention of hard immovable lumps on dogs is crucial for your furry friend's comfort and well-being.
If your dog's lump is in an uncomfortable location, such as near a joint, your vet may recommend surgical removal to prevent further discomfort.
Surgical removal is often necessary for infiltrative lipomas, which can grow quickly and surround nearby tissues, causing pain and discomfort for your pup.
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Your vet will be able to recommend the best treatment plan for your dog and their unique situation.
Preventing hygromas is key, and it starts with ensuring your large or giant breed dog doesn't become overweight or obese, as extra weight increases the risk of trauma to the tissue over bony prominences.
Providing bedding with adequate padding, such as egg-shell foam or memory foam beds, can help stabilize the hygroma and prevent further trauma.
Commercially available elbow pads can also help protect hygromas and prevent them from growing or becoming infected.
Here are some common forms of treatment for lumps on dogs:
- Surgical removal
- Amputation
- Draining (for abscesses)
- Medications
- Topical ointments (for skin conditions like hives)
- Chemotherapy (if cancerous)
- Radiation (if cancerous)
Protecting the involved area post-op is critical for good healing, so it's essential to follow your vet's advice and provide a safe and comfortable environment for your dog to recover.
Specific Conditions
Peripheral nerve sheath tumors can occur anywhere in a dog's body and are lumps that grow from the nerve cells.
These tumors can be felt as hard, immovable lumps on dogs underneath the skin when they grow close to the surface.
They are usually not painful when touched, but some dogs will bite or chew at them due to nerve irritation.
Treatment of choice for peripheral nerve sheath tumors is surgical removal of the tumor, although recurrence is common.
In some cases, amputation of affected limbs and/or radiation therapy are necessary.
Fatty tumors, on the other hand, are typically not a cause for concern unless they grow, become painful, or change texture.
If your dog's fatty tumor is in an uncomfortable location, such as near a joint, your vet may recommend having it surgically removed.
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Lipoma
Lipoma is the most common cause of lumps and bumps on a dog's skin, and it's usually benign, meaning it's not cancerous. It's also known as a "fatty tumor." Lipomas occur in adult and senior dogs, and they become more common as dogs get older. They can also happen more often in larger breeds and dogs who are very overweight.
Lipomas are not painful and grow very slowly. If a lipoma grows in an area that impacts a dog's mobility, it may need to be removed. Otherwise, it can be left alone and monitored in many instances. Some pet owners have these tumors removed for aesthetic reasons.
Lipomas are characterized as small, hemispherical lumps that can be felt just under your dog's skin. The lump will likely feel somewhat soft and you will be able to move it a little. Firmer, stationary lipomas are also fairly common.
Maintaining your dog's weight at a healthy level may help to prevent lipomas from occurring. While it may not be possible for your vet to determine the cause of your dog's lipoma, diet, genetics, chemicals in the environment, and drug interactions are thought to be contributing factors.
While lipomas are not malignant and won't metastasize, they may continue to grow and start to cause discomfort depending on their location. Each dog is unique and lipomas can grow at varying rates.
Sebaceous Gland Adenomas
Sebaceous gland adenomas are non-cancerous growths that protrude from the surface of the skin.
They are usually hairless, firm, small lumps on dogs that occur mostly on the head, neck, back, eyelids, and limbs.
In most cases, no treatment is necessary for sebaceous gland adenomas.
However, removal may be recommended if they are troublesome to the dog.
If they burst open, become irritated, or infected, treatment may be needed to prevent complications.
Mast Cell Tumor
Mast Cell Tumors are a common issue in dogs, often presenting as red, raised, firm lumps on the skin.
These lumps can vary in appearance, but a hard, bleeding lump is a typical sign of a Mast Cell Tumor.
Mast Cell Tumors can be found on the surface of the skin or just below it, making them difficult to diagnose without a needle sample.
A simple needle sample can often diagnose Mast Cell Tumors at the first visit, making early detection crucial.
If left untreated, Mast Cell Tumors can spread quickly, making surgical removal essential for treatment.
Complete surgical removal is curative if the cancer hasn't spread to other parts of the body, but follow-up radiation therapy or chemotherapy may be necessary in some cases.
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Melanomas

Melanomas are usually black lumps on a dog, but they can also be red. They're hard and immovable, often found in the oral cavity or on the toes.
These tumors are usually cancerous, especially if they're in the mouth or on the toes. Malignant melanomas are very aggressive and quickly spread to other parts of the body.
Surgery is necessary for treatment of melanomas, and in some cases, chemotherapy or radiation therapy may also be required. 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.
Dogs with light coats or parts of the dog with little coat coverage, like the belly, are more often affected.
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Squamous cell carcinomas can appear in many different ways, including as a single red lump on a dog's skin.
They can also develop as a small area of irritated, red, or ulcerated skin, or 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 usually surgery.
If the lump is removed before it spreads, dogs have a great prognosis and chance of survival.
Warts
Warts are small, light-colored lumps on a dog's skin that have a rough, jagged appearance. They can grow anywhere on the body, but are often found in or around the mouth, on the feet, or on the eyelids.
Young dogs under 2 years old are the most commonly affected by warts.
These lumps are caused by canine papillomaviruses, which are a type of virus.
Dog warts often disappear on their own as the dog develops immunity against them.
However, some warts may need to be surgically removed if they become irritated, infected, cause pain, or fail to regress on their own.
Peripheral Nerve Sheath Tumors
Peripheral nerve sheath tumors are a type of soft tissue sarcoma that can occur anywhere in a dog's body. They can grow close to the surface and be felt as hard, immovable lumps underneath the skin.
These lumps are usually not painful when touched, but some dogs may bite or chew at them due to nerve irritation. Some dogs will show signs of discomfort, but it's not always the case.
Peripheral nerve sheath tumors do not commonly spread, but they can be locally invasive. This means they can grow in size and take up space in the surrounding tissue.
Treatment of choice is surgical removal of the tumor, which may not always be successful. Unfortunately, most dogs with peripheral nerve sheath tumors may only live up to one year despite appropriate treatment.
Lymph Node
Lymph nodes are very firm and immobile.
If you can feel a lymph node, it's a bad sign, as that means it's quite large. This can be a sign of lymphoma or other cancers.
The only common cause of a lymph node being enlarged is lymphoma or other cancers. Infection can sometimes cause a single enlarged node.
Lymphoma or other cancers are the common causes of lymph node enlargement.
Lick Granuloma
Lick Granuloma is a common cause of lumps on dog legs, often presenting as an open wound that can scab over and become a lump or large bump.
This problem typically arises in dogs who lick their legs out of nerves or anxiety, and is caused by the obsessive habit of licking the same spot over and over again.
A lick granuloma can be treated with the help of topical steroids, but it's crucial that your dog is not allowed to continue chewing or biting the affected area.
In some cases, more aggressive treatments may be needed, and your dog will likely need to wear a cone collar until the problem clears up.
Anti-anxiety medication may also be necessary to help resolve the underlying problem.
Abscess
An abscess is a swollen pocket of skin that is usually filled with fluid or pus.
It's often a sign of an infection on the surface of the skin, and can be caused by skin injuries like cuts or bite wounds.
Abscesses can be firm or movable, and they usually cause a lot of pain.
An abscess is an acute problem, which means it happens fairly suddenly instead of growing over time.
If your dog has an abscess, you'll need to bring them to the veterinarian to drain the pus and may need to take antibiotics afterward.
Fortunately, your dog should recover fully with no trouble.
Is a Hygroma a Tumor? What Causes It?
Hygromas are not tumors, but rather a response to repeated trauma to the tissue over a bony prominence. This is why the elbow is the most common site for hygromas to develop, especially in large and giant breed dogs.
The repeated trauma of lying down on hard surfaces, such as hardwood, tile, or concrete floors, can produce an inflammatory response in the tissue under the skin over the elbow. This is because the body tries to protect the inflamed area by creating a "pillow" of sorts.
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Dogs that are sedentary and spend more time lying down are more likely to develop hygromas. This is because the time spent resting and sleeping on hard surfaces increases the pressure on the hygroma site.
Any large or giant breed dog of any age is potentially at risk of developing a hygroma if they spend time resting and sleeping on hard surfaces.
Frequently Asked Questions
Are cancerous lumps in dogs hard or soft?
Mast cell tumors in dogs are usually firm to the touch, often feeling solid and irregularly shaped. If you suspect a lump on your dog, it's essential to consult a veterinarian for proper diagnosis and treatment.
Sources
- https://www.denvervet.com/site/blog/2022/08/31/fatty-tumor-lipoma-dog
- https://heartandpaw.com/pet-parent-resources/lump-on-my-dogs-leg
- https://www.walkervillevet.com.au/blog/lipoma-fatty-tumour-dog/
- https://www.greatpetcare.com/dog-health/lumps-on-dogs/
- https://vcahospitals.com/know-your-pet/hygroma-in-dogs
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