Lump or Tumor on a Cat's Paw: Causes and When to Worry

Name: Lump or Tumor on a Cat's Paw: Causes and When to Worry
Creator: Dr. Zubair Khalid

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-10-03

This article is educational and is not a substitute for veterinary diagnosis or treatment.

A lump on a cat's paw can be many things, and most of them are not cancer. Benign growths, cysts, infections, and foreign bodies are common causes of a cat tumor on paw or a lump between cat toes. The only way to know for sure is to have a veterinarian examine the mass, because benign and malignant tumors can look identical from the outside [1].

Quick Answer

Most paw lumps in cats are benign, but benign and cancerous tumors cannot be told apart by look or feel alone [1].
A veterinarian can sample the lump with a fine needle aspiration or biopsy to identify the cells [1].
Any mass that is growing, bleeding, ulcerated, or causing limping needs prompt veterinary assessment.
After surgical removal, the tissue should go to a laboratory to confirm the tumor type and whether clean margins were achieved [1].
Do not squeeze, poke, or try to remove a paw lump at home. You can cause bleeding, infection, or spread of cells.

What a Paw Lump Looks Like and What Is Normal

Cats' paws take a lot of wear. The paw pads are thick, hairless cushions, and the spaces between the toes and the skin along the top of the foot are common places for lumps to appear. You might notice a cat cyst on paw, a small firm bump, a soft swelling, or a scab that will not heal.

Some lumps are normal anatomy. Paw pads themselves can look uneven, and older cats sometimes develop harmless thickened areas from years of walking and jumping. A cat's toes can also have small calluses or pigment spots that are not tumors.

What matters is change. A lump that has been the same size for years is less concerning than one that appeared last week and has doubled. A mass that is warm, painful, oozing, or bleeding is more urgent than a smooth, cool, movable bump.

Main Causes of a Lump on a Cat's Paw

The list of possible causes is long. Here are the most common categories, along with clues that help your veterinarian sort them out.

Cause	Typical clues	How urgent
Benign skin tumors (papillomas, adenomas)	Slow growing, smooth or wart-like, not painful, often on haired skin	Routine visit
Cysts and fluid pockets	Soft, movable, may drain clear or bloody fluid, often between toes	Routine to urgent if infected
Abscess or infection	Warm, painful, swollen, may drain pus, cat may limp or lick	Same day
Foreign body (thorn, splinter, grass awn)	Sudden swelling, licking, a visible wound or draining tract	Same day
Squamous cell carcinoma	Crusty, ulcerated, non-healing sore, often on sun-exposed or haired skin [2]	Prompt visit
Soft tissue sarcoma (including nerve sheath tumors)	Firm, deep, fixed mass that may infiltrate surrounding tissue [3]	Prompt visit
Plasma cell neoplasia	Uncommon in cats, can involve multiple sites, may respond to radiation and chemotherapy [4]	Prompt visit
Other cancers (lymphoma, carcinoma, sarcoma)	Variable, may involve internal organs or lymph nodes [5]	Prompt visit

Benign tumors do not invade nearby tissue and do not spread to other parts of the body. Malignant tumors can invade surrounding tissue and spread to distant organs [1]. That difference is why sampling matters.

Papillomavirus infection has been linked to some skin cancers in cats. One cat with multicentric squamous cell carcinoma in situ was found to be coinfected with two different feline papillomaviruses, and the lesions cleared with topical imiquimod cream applied twice weekly for 3 months [2]. This is a single case report, so it does not mean every paw lump is caused by papillomavirus or that imiquimod is right for your cat. It does show that some skin tumors in cats can be managed medically instead of surgically.

Nerve sheath tumors are not uncommon in cats and usually arise from nerves in the skin or under the skin of the head, neck, or limbs [3]. They can feel like a firm lump under the skin and may be painful if they press on a nerve.

Red Flags That Make It an Emergency

Some signs mean you should not wait for a routine appointment.

Your cat is limping badly or will not put weight on the paw.
The paw is swollen, hot, and painful to touch.
The lump is bleeding and will not stop.
Your cat is crying, hiding, or refusing to eat.
The toe or paw looks dark, cold, or discolored.
There is a foul smell or pus draining from the mass.
Your cat has trouble breathing along with the paw lump.

Breathing difficulty is always an emergency. One cat with a rare tracheal tumor presented with respiratory distress, and the tumor was confirmed only after death [6]. That case involved the airway, not the paw, but it shows how quickly respiratory signs can become critical.

If your cat has a lump on the paw plus any of these signs, call your veterinarian or an emergency clinic right away.

What You Can Safely Do at Home While You Wait

You cannot diagnose or treat a paw tumor at home. What you can do is keep your cat comfortable and prevent the lump from getting worse.

Do not squeeze, lance, or try to pop the lump. This can cause infection or bleeding.
Do not apply human creams, ointments, or essential oils to the paw. Cats lick their paws and can swallow products that are toxic to them.
Check the paw daily for changes in size, color, or drainage. Take a photo with a ruler or coin next to the lump so you can compare over time.
Keep your cat indoors to limit dirt and bacteria getting into an open sore.
If your cat is licking the paw constantly, ask your veterinarian about a cone or a soft paw cover. Do not use a tight bandage, which can cut off circulation.
Note any limping, appetite changes, or behavior changes. Bring these notes to the visit.

If you are not sure whether the lump is new, compare it to the other paws. Symmetry helps. A lump on one paw that has no match on the others is more likely to be a growth than normal anatomy.

For more on lumps elsewhere on the body, see Cat Skin Bumps and Lumps: When to See a Vet and When to Monitor.

What the Veterinarian Will Check and Test

Your veterinarian will start with a physical exam. They will look at the lump, feel its size, depth, and mobility, and check the nearby lymph nodes. They will also watch your cat walk to see if the paw is painful or if the limp comes from higher up the leg.

The next step is usually a fine needle aspiration. This uses a thin needle to collect cells from the mass, which are then examined under a microscope [1]. It is quick, does not usually require sedation, and can often tell the difference between a cyst, an infection, and a tumor. Sometimes it cannot give a final answer, and a biopsy is needed. A biopsy removes a small piece of tissue for laboratory evaluation [1].

If the lump is removed surgically, the tissue should be sent to a laboratory. The pathologist confirms the tumor type and checks the margins. Clean or wide margins mean tumor cells are far from the edge of the removed tissue, so it is unlikely any remain. Narrow margins mean cells are close to the edge. Dirty margins mean tumor cells extend to the edge, so some may still be in your cat's body [1]. Margin status helps your veterinarian decide whether a second surgery or other treatment is needed.

Blood work and imaging may be recommended. Chest X-rays or ultrasound can check for spread to other organs. In one study of 187 cats with kidney tumors, lymphoma was the most common type and was more often bilateral, while carcinoma was more often a single mass [5]. That study looked at kidney tumors, not paw tumors, but it shows how imaging and sampling work together to identify cancer type and guide treatment.

Treatment depends on the diagnosis. Benign tumors are often cured by surgery alone [1]. Some cancers may need wider surgery, radiation, or chemotherapy. One cat with plasma cell neoplasia was treated with radiation and systemic chemotherapy, and follow-up imaging showed complete resolution [4]. That is one case, and outcomes vary widely by tumor type and stage.

For a look at what testing and treatment may cost, see Cat Skin Bumps and Lumps: What the Vet Will Do and How Much It Costs.

Monitoring and Prevention

You cannot prevent every paw lump, but you can catch problems early.

Check your cat's paws monthly. Look between the toes, on the pads, and along the top of the foot.
Keep your cat indoors or in a safe outdoor enclosure to reduce trauma and exposure to foreign bodies.
Trim long hair between the toes if it traps debris, but do not cut the paw pads.
Keep your cat's weight healthy. Extra weight puts more stress on the paws and can make limping worse.
If your cat has a history of skin cancer, ask your veterinarian how often to recheck. Some cats need more frequent monitoring.
Follow up on any lump that was sampled but not removed. Some benign lumps still need to be watched for change.

Papillomavirus is thought to play a role in some feline skin cancers, and one cat with multicentric carcinoma in situ responded to topical imiquimod [2]. There is no vaccine for feline papillomavirus in general use, and prevention is not well established in veterinary research. Keeping your cat indoors and avoiding contact with unknown cats may reduce exposure, but this has not been proven for paw tumors specifically.

If your cat has other skin or respiratory signs, these articles may help: Cat Skin Rash with Swelling: When to Worry, Cat Coughing: When Should You Worry?, and Cat Sneezing: Common Causes and When to Worry.

Limitations and When to Contact a Veterinarian

No article can tell you whether your cat's paw lump is cancer. Only a veterinarian can examine the mass, sample it, and interpret the results for your individual cat.

Contact your veterinarian the same day if your cat is limping, the lump is painful or draining, or your cat is licking the paw constantly. Go to an emergency clinic now if your cat is struggling to breathe, the paw is bleeding heavily, or your cat collapses or seems unable to stand. Schedule a routine visit if you find a new lump that is not painful and your cat is acting normal.

Do not wait to see if a lump goes away on its own. Some benign lumps do shrink, but some cancers grow quickly. Early assessment gives you more options.

Frequently Asked Questions

Can a cat cyst on the paw turn into cancer?

A true cyst does not turn into cancer. Cysts are fluid-filled pockets, and cancers are abnormal cell growths. However, a lump that looks like a cyst can sometimes be a tumor with a cystic center, so sampling is the only way to know.

Is a lump between cat toes always serious?

No. Lumps between the toes are often cysts, foreign body reactions, or infections. They can also be tumors. Because the area is tight and hard to keep clean, any lump there tends to cause licking and limping, which makes it worth a veterinary visit.

How fast do paw tumors grow in cats?

Growth rates vary widely by tumor type. Some benign tumors stay the same size for years, while some cancers can double in weeks. Your veterinarian can measure the lump and track changes over time.

Will my cat need surgery to remove a paw lump?

Not always. Cysts and some infections may be treated with drainage, antibiotics, or observation. Tumors are usually removed surgically, and the tissue is sent to a laboratory to confirm the type and margins [1]. Some skin cancers in cats have been managed with topical medication in reported cases [2], but this depends on the diagnosis.

Can I use human antibiotic ointment on my cat's paw lump?

No. Cats lick their paws and can swallow ointments that are not made for them. Some human products contain ingredients that are toxic to cats. Ask your veterinarian for a cat-safe product if one is needed.

References

Tumors of the Skin in Cats - Cat Owners. Merck Veterinary Manual.
Coinfection with Different Feline Papillomaviruses in a Cat with Multicentric Squamous Cell Carcinoma In Situ. Animals : an open access journal from MDPI, 2026.
Malignant nerve sheath tumor infiltrating the epididymis of an inguinal cryptorchid testis in a domestic shorthair cat. JFMS open reports, 2026.
Multicentric Round Cell Neoplasia with Plasmacytic Differentiation in a Cat with Systemic Progression: Multimodal Imaging and Treatment Response. Animals : an open access journal from MDPI, 2026.
Ultrasonographic features of feline renal neoplasia: a retrospective study on 187 cases. Journal of feline medicine and surgery, 2026.
Tracheal Squamous Cell Carcinoma in an Adult Cat. Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association, 2026.