Lump or Growth on Your Cat's Ear: Causes and Next Steps

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

A cat ear growth can be a harmless cyst, a wart, or a tumor, and only a veterinarian can tell the difference. Lumps on the ear flap are often benign, but growths inside the ear canal are more likely to be serious, especially in older cats [1]. This article is educational and is not a substitute for veterinary diagnosis or treatment.

Quick Answer

• Any new lump on the ear flap or inside the ear canal deserves a veterinary look, because benign and malignant growths can look identical from the outside.
• Ear canal tumors in cats are more often malignant than benign, particularly after age 11 [1].
• A growth that bleeds, grows quickly, smells bad, or comes with discharge from one ear needs prompt sampling, not watchful waiting [1].
• Benign tumors can often be removed with laser surgery through a video otoscope, which avoids opening the ear canal surgically [2].
• Do not squeeze, poke, or try to remove the lump at home, and do not apply human medications or ear cleaners to a growth.

What You Are Seeing and What Is Normal

The feline ear has two main parts you can inspect. The pinna, or ear flap, is the flat cartilage covered in thin skin and fur. The ear canal runs from the opening down to the eardrum, and it bends in an L shape, so you cannot see most of it without a scope.

Normal ear tissue is smooth, pale pink, and symmetrical between the two ears. Small flat freckles or dark spots on the flap are common in orange and calico cats and are usually just pigment. A true raised bump, a fleshy stalk, a scab that will not heal, or a swelling that changes the shape of the ear opening is not normal.

Some owners notice a lump while petting the ear. Others notice a problem because the cat shakes its head, scratches one ear, or has a bad smell from one side. Growths deep in the canal are usually found by a veterinarian during an ear exam, not by the owner at home.

Main Causes of a Cat Ear Growth

Growths on and in the ear come from many tissue types, including skin, earwax and oil glands, bone, connective tissue, muscle, and deeper skin layers [1]. Tumors of the outer ear and external canal are more common than tumors of the middle or inner ear [1].

Table: Cause | Typical clues | How urgent

Long-term inflammation in the ear canal can lead to abnormal tissue growth and eventually tumors [1]. Bacterial infections that increase earwax production might also promote cancerous changes [1]. This is one reason chronic ear problems should be managed, not ignored.

If your cat also has hair loss on the ear flaps, that can point to a different set of causes, including allergies, mites, or ringworm. See Cat Hair Loss on Ears: Causes and What to Do for that pattern. If the skin looks scaly and circular, Ringworm on a Cat's Ear: Signs, Treatment, and Cleaning covers what to expect.

Growths on the Ear Flap

Lumps on the pinna are often benign cysts, warts, or sebaceous growths. They tend to be slow growing, movable, and covered by normal skin. Sun exposure matters here. Cats with white or lightly pigmented ears are at higher risk of sun-related skin cancer on the ear tips, so a crusty sore on a white ear should never be watched for months.

Growths Inside the Ear Canal

This is where things get more serious. In cats, ear canal tumors are more often malignant than benign, especially after age 11 [1]. Signs include ongoing discharge from one ear that can be waxy, pus-filled, or bloody, a foul odor, head shaking, scratching, swelling, draining abscesses below the ear, or deafness [1]. If the middle or inner ear is involved, you may see loss of balance, a head tilt, or neurological signs [1].

Persistent one-sided inflammation that does not respond to treatment raises concern for a tumor [1]. That pattern, one bad ear that keeps coming back after treatment, is a classic reason to look deeper with imaging and a biopsy.

Polyps and Other Masses

Inflammatory polyps are benign fleshy growths that can sit in the canal or extend through the eardrum [1]. They are more common in younger cats. A case report described a 9-year-old cat with a polypoid mass in the left ear canal that penetrated the eardrum, and the tumor was later diagnosed as a tympanic papillary adenoma after full surgical removal and histology [3]. That tumor recurred within 17 months, which shows why follow-up matters even after successful surgery [3].

Red Flags That Make It an Emergency

Go to an emergency clinic now if your cat has any of these:

• Sudden severe head tilt, circling, falling, or inability to stand, which can mean inner ear or brain involvement [1]
• A growth that is bleeding heavily and will not stop
• Facial paralysis, drooping eyelid, or drooling on one side
• A swelling below the ear that is hot, painful, and rapidly enlarging
• Difficulty breathing or collapse

Call your veterinarian the same day for these:

• Discharge from one ear that is bloody or pus-filled [1]
• Foul odor from one ear [1]
• A lump that has doubled in size over days to weeks
• A sore on the ear that oozes, crusts, or bleeds when touched
• Head shaking or scratching that is constant and interferes with eating or sleeping

If your cat is scratching but you do not see a lump, the cause may be mites, allergies, or infection. Why Is My Cat Scratching Its Ears? walks through those possibilities.

Safe Things You Can Do at Home While Waiting

You cannot diagnose the lump at home, but you can keep your cat comfortable and avoid making things worse.

• Take a photo of the growth next to a coin or ruler so you can track size changes.
• Note the date you first saw it and whether it has changed.
• Keep the ear dry. Do not flush the ear or use cotton swabs inside the canal.
• Do not squeeze, scratch, or pick at the lump. Do not try to pop it.
• Do not apply human creams, antibiotic ointments, hydrogen peroxide, or alcohol to the ear.
• Use a soft cloth to wipe only the outer flap if there is discharge, and stop if it causes pain.
• If your cat is scratching, ask your vet about a cone collar to prevent self-trauma.
• Keep your cat indoors and away from sun exposure if the lump is on a white ear tip.

If the ear is swollen, warm, and painful, that pattern can also occur with a deep ear infection or a hematoma. Cat Ear Infection with Swelling: What to Do and When to Worry explains how those are handled.

What Your Veterinarian Will Check and Test

The visit starts with a full history. Your vet will ask when you first noticed the lump, whether it has changed, whether the cat has had ear problems before, and whether the cat goes outside or has sun exposure.

Physical and Otoscopic Exam

Your vet will examine both ears, the pinna, the canal opening, and the area below the ear. A video otoscope lets the vet see the canal and eardrum clearly. Ceruminous gland tumors are best seen in a clean ear using a video otoscope, and they can look smooth or multilobulated, or they can sit on a stalk [2].

Sampling the Mass

This is the step that answers the question. Options include fine needle aspiration, which pulls cells with a thin needle, and biopsy, which removes a piece of tissue for lab analysis. Biopsy of the mass can be helpful for diagnosis [2].

One caution your vet knows well: superficial ear canal biopsies are often incorrectly reported as polyps with granulation tissue covered by epithelium and bacteria or inflammatory cells, while deep en bloc biopsies of the same tissue are often correctly reported as tumors [2]. If the first result comes back as inflammation, ask whether a deeper sample is needed.

Imaging

CT or MRI can assess the tympanic bulla more completely and determine how far a tumor has invaded, especially with malignant tumors [2]. In the case report of the cat with a tympanic papillary adenoma, CT of the head revealed an irregular mass in the left tympanic bulla that had not been obvious on the initial exam [3]. Imaging is often the step that shows whether a growth is confined to the canal or has moved into the middle ear.

Treatment Options

Benign ear canal tumors can be surgically removed with a lateral ear canal resection for access to the mass [2]. Laser surgery, especially with a video otoscope, has made removal of these tumors relatively easy and avoids the need to open the canal surgically [2]. More extensive tumors may need a total ear canal ablation, which removes the canal and bulla. Your veterinarian will recommend the approach based on the biopsy result, the location, and your cat's overall health.

Prevention and Monitoring

You cannot prevent every growth, but you can lower some risks and catch problems early.

• Manage chronic ear infections. Long-term ear canal inflammation can lead to abnormal tissue growth and tumors [1].
• Keep white-eared cats out of strong sun, especially during peak hours.
• Check both ears monthly. Run your fingers along the flap and look inside the opening.
• Photograph any new bump and measure it.
• Keep follow-up appointments after removal. The tympanic papillary adenoma case recurred within 17 months after surgery [3], so recurrence is a real possibility with some tumors.
• Ask your vet how often rechecks should happen for your cat's specific diagnosis.

Limitations and When to Contact a Veterinarian

No article can tell you whether your cat's lump is benign. Only a veterinarian who examines the tissue can do that, and individual cases need a veterinarian's hands-on assessment.

Contact an emergency clinic now for balance loss, head tilt, collapse, heavy bleeding, or one-sided facial paralysis [1]. Call your vet the same day for bloody or pus-filled discharge from one ear, foul odor, a rapidly growing lump, or a non-healing sore [1]. Schedule a routine visit for a small, stable, painless bump on the ear flap, but do not wait months if it changes.

Frequently Asked Questions

Is a lump on my cat's ear always cancer?

No. Many lumps on the ear flap are benign cysts, warts, or harmless skin growths. However, growths inside the ear canal are more often malignant than benign in cats, especially after age 11, so location matters a great deal [1].

Can I just watch a small bump on the ear flap?

You can monitor a small, stable, painless bump for a short time if your veterinarian agrees. Take a photo with a ruler and check it weekly. If it grows, bleeds, changes color, or bothers your cat, book a visit right away.

Will my cat need surgery to remove the growth?

Not always. Some growths can be sampled and monitored, and some benign tumors can be removed with laser surgery through a video otoscope without opening the ear canal [2]. Larger or deeper tumors may need more extensive surgery, and your vet will discuss the options after diagnosis.

How does a vet tell a cyst from a tumor?

A vet uses otoscopy, fine needle aspiration, and biopsy. Superficial ear canal samples can be misleading and may be reported as inflammation when a tumor is present, so deep biopsies are often needed for an accurate answer [2]. Imaging with CT or MRI may follow if the middle ear is involved [2].

Can an ear growth come back after removal?

Yes, some can. In one reported case, a tympanic papillary adenoma recurred within 17 months after surgical removal [3]. That is why recheck exams and monitoring for new discharge, odor, or head shaking after surgery are so important.

Related Articles

• Cat Hair Loss on Ears: Causes and What to Do
• Ringworm on a Cat's Ear: Signs, Treatment, and Cleaning
• Why Is My Cat Scratching Its Ears?
• Cat Ear Infection with Swelling: What to Do and When to Worry
• Cat Scratching Their Ears
• Cat Skin Bumps and Lumps: When to See a Vet and When to Monitor
• Cancer in a Cat's Ear: Tumors and Warning Signs
• Cat Ear Zit or Bump: Causes and When to Worry
• Cat Skin Growths: Lumps, Scaling, and When to Worry

References

1. Tumors of the Ear Canal in Cats - Cat Owners. Merck Veterinary Manual.
2. Ceruminous Gland Tumors in Small Animals - Ear Disorders. Merck Veterinary Manual.
3. Tympanic papillary adenoma (tympanic papilloma) in a cat - a case report. Journal of comparative pathology, 2026.

Further Reading

• Merck Veterinary Manual: Cat Owners
• Cornell Feline Health Center: Health Information
• American Veterinary Medical Association: Pet Care