9 Common Dog Lumps, Tumors, Cysts, and Warts (with Pictures)

Old dog lumps and bumps aren’t usually any different to the type of lumps and bumps younger dogs get.

However, there are some kinds of lumps or growths that are more often seen in middle-aged to older dogs, these include lipomas, mast cell tumors and warts.

Older dog with a wart on his muzzle

Other types of dog skin bumps, lumps or growths include sebaceous cysts and tumors (both benign and malignant).

Common Types of Lump and Bumps (With Pictures)

It can be difficult to tell the difference between a benign and a more serious, potentially cancerous tumor or growth. Any new (or growing/changing) lump always needs to be examined by your veterinarian.

veterinarian and dog

We’ll start with the ones that are  more common in senior dogs, but any dog, at any age, can develop any of the lumps, bumps or growths discussed on this page.

1. Lipomas on Dogs

Lipomas are the most common benign (ie NON-cancerous) growth seen in dogs. Each lipoma is made up of a group of fat cells which forms a soft round, or oval, lump usually located just below your dog’s skin.

lipoma on a dog

They’re generally easy to move around and don’t feel as though they are connected to deeper tissue in the body. Lipomas are usually slow growing. Sometimes they will stop growing, but don’t often disappear or get smaller.

Although these common old dog lumps are not dangerous in themselves, if a lipoma gets too big it can cause discomfort for your golden oldie.

Depending on where they’re located, lipomas can cause difficulty with movement, or even put pressure on internal organs.

Causes of lipomas on dogs:

Although many veterinarians consider these fatty lumps a normal part of the aging process in dogs, they can also be a sign of certain health conditions.

Dogs who are overweight are more prone to developing lipomas. Dogs with hypothyroidism and other metabolic problems are also at an above-average risk of having lipomas.

WATCH: 3 Important Tips To Care For an Old Dog [VET VIDEO]

Some veterinarians believe that hormone imbalances and a build up of toxins in the body also contribute to the formation of these fatty dog lumps.

Finally, certain breeds seem to be predisposed to getting lipomas, especially later in life, these include Labrador Retrievers, Doberman Pinschers and Shetland Sheepdogs. Overall, many senior dogs have at least one lipoma, and some have several.

How to treat lipomas on dogs:

Veterinary opinion on the best way to deal with lipomas is varied, and your vet will likely have his own take on this. However, it’s always advisable to have any lump, especially an old dog lump, biopsied to make sure that it IS benign and not anything more sinister.

A needle aspiration is a very quick and simple process, or a punch biopsy is also straightforward and often only requires a local anesthetic. Either will give you peace of mind.

West Highland White Terrier needle biopsy

For verified lipomas the choice is either to leave them be, or to have them surgically removed under anesthetic.

Anesthesia in older dogs is a bit more complicated, and a little more risky, than it is in younger dogs so obviously that is something to consider. However, it’s not age itself which increases anesthetic risk; it’s the concurrent illnesses which occur more frequently with old age.

It’s important to make sure that the need outweighs the risks.

Some lipomas that are left to their own devices will stay the same size, others will keep growing.

The decision of whether to remove one or not depends on its location, size and whether or not it is affecting your dog negatively.

Occasionally a fatty lipoma can move from the pocket it is in below skin level and invade deeper tissue. This is called an infiltrative fatty tumor and will usually feel firmer and be immobile as they are connected to muscle or tissue. Lipomas of this type are even more difficult to tell apart from other types of tumors or lumps so it’s doubly important to have an aspiration or biopsy done by your vet. Learn more about lipomas in dogs.

2. Dog Warts

Warts (also called Papillomas) are the other most common type of old dog lumps and can occur on your dog’s skin, on his eyelids, paw pads, between the toes, around the genital area or in his mouth.

wart on a black dog

They can show up as a single small lump, or as a group or cluster of tiny lumps which look a little bit like a cauliflower floret.

Older dogs tend to develop the single warts, whereas puppies are more prone to the multiple grouping, however either type of papilloma can develop on a dog of any age.

Disclaimer: This website’s content is not meant to be a substitute for veterinary care. Always consult with your local veterinarian for health decisions. Learn more.

Warts on dogs are most often benign and will often disappear of their own accord after a few months. Occasionally they can be, or become, cancerous so any wart that is a long-term issue, or that changes in color/size/look needs to be investigated by a vet.

Causes of warts on dogs:

Canine warts are caused by a virus and are contagious from dog to dog, but luckily not from dog to human, or to cat.

This virus tends to take hold best in dogs whose immune system is weak (which is why puppies and older dogs are especially at risk).

Dogs who have been on corticosteroids for any extended period are also more susceptible, as the steroids weaken the immune system.

The same can be said for dogs who are suffering from chronic health problems.

Treating warts on dogs:

Simple old dog lumps like benign warts usually don’t need any treatment unless they get infected, gets in the way, or becomes irritated.

This can happen if a dog licks or scratches at the wart, or it is in an area that’s rubbed by a collar or harness for example.

Of course, you’ll want your vet to look at any new growth, lump, or bump on your senior dog just to make sure that it isn’t anything to worry about.

Once confirmed as a benign wart all you need to do is to keep an eye on it to make sure that it doesn’t grow, change, or become infected.

If a wart starts to bleed, grow, or looks more like an ulcer than a wart, it needs to be re-evaluated by your veterinarian as those changes could be signs of malignancy. Any wart that has variegated color (ie dark/light areas) and is on his muzzle, lips or eyelids also needs to get a close look from your vet for the same reason.

If the wart, or warts, start to cause a problem for your dog and are uncomfortable or irritating to him, cryosurgery (freezing them off) is an option. But there is some discomfort related to that procedure and the stress of it can lower the immune system even more.

Vitamin E Oil applied directly to the wart can sometimes cause it to shrink and eventually disappear.

Boosting your golden oldie’s immune system, making sure his diet is optimal, and treating any underlying health issues properly will all help his body to be stronger and healthier overall… and reduce his chances of getting warts and other old dog lumps such as lipomas too.

View 7 pictures of dog warts on this page.

3. Sebaceous Cysts on Dogs

Sebaceous cysts are not predominantly old dog lumps. They’re common in dogs of all ages and can occur singly or your dog could have several of them.

Sebaceous Cyst on dog

These types of cysts can be tiny or grow up to an inch or more in size. They tend to resemble a human ‘pimple’, just larger.

Causes of dog sebaceous cysts:

A sebaceous cyst forms when a pore or hair follicle in your dog’s skin becomes blocked or clogged. Matter (oil, skin cells, dirt, and such) collects behind the blocked pore and forms the cyst just below the skin.

As always, it can be difficult to tell the difference between all the different types of old dog lumps you might find… always have your vet take a look and make the diagnosis.

Treating sebaceous cysts in dogs:

Sebaceous cysts are benign and generally don’t need any treatment as they resolve on their own in one of three ways: ‘Come to a head’ and burst or ooze out the pus/gunk inside. This is yukky, and it’s important to keep the area clean and dry to prevent infection.

Become walled-in by the surrounding tissue and form firm lumps which don’t burst, but they also don’t go away. Over time the contents of the sebaceous cyst are re-absorbed back into the body and the lump disappears.

Dog having cyst removed from paw

You may need to treat a sebaceous cyst on your old dog if:

  • If the area around the cyst becomes red, swollen or hot.
  • If the cyst becomes so large it’s painful or difficult for your dog.
  • The location of the cysts causes pain or limits movement
  • Your dog won’t stop licking/irritating it

In both cases you need to have your vet take a look as there could either be infection at the site, or the cyst needs to be removed. Learn more about sebaceous cysts in dogs.

4. Malignant Skin Tumors in Dogs

Although most old dog lumps and bumps are benign, cancerous tumors can develop and it’s often difficult to tell the difference between the two types of growth.

ANY new lump, bump, growth, or cyst needs to be examined by your veterinarian so that he can diagnose it properly. Cancerous, or malignant, tumors of the skin can be small or large. They may itch or cause senior dog some discomfort. They may do neither.

Just as with cancer in humans, the causes of cancer aren’t fully understood. Injury/trauma, sun damage and certain illnesses may play a role in the development of malignant skin tumors in dogs. Genetics also play their part and certain breeds are more susceptible to developing specific cancers than others.

Malignant skin tumors in dogs include: mast cell tumors, mammary gland tumors, malignant melanoma and squamous cell carcinoma. Mammary gland tumors are not skin tumors as such, but they’re seen/felt in skin/tissue around your dog’s teats.

4-A: Mast Cell Tumors

In healthy dogs, mast cells are the part of the immune system that releases histamine in response to allergies.

Image by Joel Mills (Own work) GFDL CC-BY-SA-3.0 or CC BY-SA 2.5-2.0-1.0,
via Wikimedia Commons

Mast cell tumors are more often seen in middle aged and older dogs but can affect younger dogs too. These old dog lumps are not always malignant, but it’s impossible to know which ones are and which aren’t without a needle aspiration biopsy.

Mast cell tumors can vary a LOT in appearance; usually they’re a fairly smooth, round growth visible on the skin. Other times they can look like a wart, or resemble a lipoma, and sometimes they are red in color.

Mast cell tumors are more common in:

  • Beagle
  • Boxer
  • Boston Terrier
  • Bulldog
  • Bull Mastiff
  • German Shorthaired Pointer
  • Golden Retriever
  • Great Dane
  • Labrador Retriever
  • Pug
  • Rhodesian Ridgeback
  • Scottish Terrier
  • Shar Pei
  • Staffordshire Bull Terrier
  • Weimaraner

4-B: Melanoma

Melanoma tumors are dark and can be small, or large, flat or raised. They can be either benign or malignant, so they shouldn’t be ignored.

potential melanoma

If a dog has malignant melanoma, it’s usually an aggressive cancer which spreads throughout the body quickly, so the lesion needs to be surgically removed as quickly as possible.

Only a veterinarian can tell the difference between a benign and a malignant melanoma by doing a biopsy.

Most malignant melanomas in dogs grow in/around the mouth or in other mucus membranes, but they can also be found in other areas.

Melanomas are more common in:

  • Anatolian Shepherd
  • Cocker Spaniel
  • Chow Chow
  • Dachshund
  • Golden Retriever
  • Gordon Setter
  • Poodle
  • Scottish Terrier

4-C: Squamous Cell Carcinoma

Squamous cell carcinomas in dogs are fairly rare, and they are not as aggressive in terms of spreading as melanoma or mast cell tumors are.

potential Squamous Cell Carcinoma

These types of malignant tumors are usually found on areas of skin that are bare, or have little hair, and are more common in dogs with light colored skin.

Squamous cell tumors in dogs can be raised lumps or nodules, or flatter areas of ulcerated skin. They can sometimes resemble warts.

Squamous cell tumors are more common in:

  • Basset Hound
  • Beagle
  • Bull Terrier
  • Collies
  • Keeshonds
  • Schnauzers (standard)

Treating Malignant Skin Tumors in Dogs

The best way to treat malignant or cancerous lumps in dogs is to remove them surgically, and as quickly as possible. The smaller the lump the easier the surgery and the less tissue which must be removed.

Acting fast also helps to reduce the chances of the cancerous cells metastasizing (traveling) into other tissues, organs and lymph nodes. Sometimes radiation therapy, chemotherapy or other treatments are recommended in addition to removing the tumor.

The exact treatment options will be decided by your vet and consider the size and location of the tumor and whether it has spread to other areas of the body.

Black Spots on Dog’s Skin

Most instances of dark or black-colored spots on the skin of dogs are hyperpigmentation. Hyperpigmentation occurs when there is an increase in dark pigmentation of the skin.

hyperpigmentation and black spots on a dog's skin

The pigment of skin cells is what gives the skin its color. The substance in these cells that make this color is called melanin. Specialized cells in the skin produce melanin. If these cells become damaged, it may affect melanin production.

Most instances of dark or black colored spots on the skin of dogs are hyperpigmentation. Hyperpigmentation occurs when there is an increase in dark pigmentation of the skin.

The pigment of skin cells is what gives the skin its color. The substance in these cells that make this color is called melanin. Specialized cells in the skin produce melanin. If these cells become damaged, it may affect melanin production.

If your dog has hyperpigmentation or black spots, you may notice other changes to the skin in this area as well.  The skin may become rough, scaly, red around the area, itchy, or crusty. Many of these changes are caused by the affected skin thickening.

The skin may become rough, scaly, red around the area, itchy, or crusty. Many of these changes are caused by the affected skin thickening. Learn more about black spots on a dog’s skin.

Overview: Pictures of 9 Common Dog Lumps, Tumors, Warts and Cysts

infographic showing common lumps, warts, tumors or cysts for dogs

Click here to see a list of pictures of lumps, tumors, cysts or warts that are often observed on dogs as they get older.  Pictures are provided as examples only, as it is usually not possible to determine the true nature of a lump without testing and analysis.

pictures of dog tumors, cysts, lumps and warts

Read More About Dog’s Lumps and Bumps:

  • Dr. Winnie earned a Bachelor of Science in Psychology from Duke University, a Masters of Science in Biology from St Georges University, and graduated from the University of Pretoria Veterinary School in South Africa. She is a full-time Veterinarian in South Africa specializing in internal medicine for large breed dogs.

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Disclaimer: This website’s content is not meant to be a substitute for veterinary care, diagnosis, or treatment. Always consult with your veterinarian to determine the best course of action. Read More.

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