CONDITION

Squamous Cell Carcinoma of the Pinna in Cats

Squamous cell carcinoma of the pinna is a form of skin cancer that arises in the thin, flat cells lining the surface of the ear flap. In cats, this tends to occur in areas where sun exposure has damaged the skin over time, particularly in animals with white or pale ears. The condition develops slowly, often beginning as persistent roughness, redness, or small crusted areas that may come and go before progressing to open sores or thickened patches that do not heal. Owners often notice changes that initially resemble minor injuries or irritation—small scabs, recurring scratches, or areas that bleed easily when touched. These signs may be present for weeks or months before the pattern becomes clear. Because the changes can be subtle at first, and because ear tips are naturally exposed and occasionally injured, it is not always obvious when something more persistent is unfolding. This page explores what squamous cell carcinoma of the pinna can look like in its early and later stages, what is happening in the skin as the condition develops, how veterinary surgeons investigate and confirm the diagnosis, and what approaches exist for managing it. The aim is to help orient you to the condition and the questions that may arise as you and your veterinary team work through what is happening.

Why this matters now

This condition tends to appear in older cats, often those aged ten years or more, and is strongly associated with cumulative sun exposure over a lifetime. White-eared cats and those with pale or non-pigmented ear tips are particularly vulnerable, as melanin—the pigment that offers some protection against ultraviolet damage—is sparse or absent in these areas. Cats who spend significant time outdoors, particularly in sunny climates or at higher altitudes where UV intensity is greater, accumulate the kind of repetitive cellular damage that can eventually give rise to squamous cell carcinoma.

The condition typically develops slowly, often over months to years. Early changes may be subtle and intermittent—areas of redness or crusting that seem to improve and then return—before becoming more persistent and visibly abnormal. In some cases, the progression remains localised to a small area of the pinna for an extended period, whilst in others the tissue changes spread more broadly across the ear tip or involve both ears. The timeframe and pattern can vary considerably between individual animals.

Signals & patterns

Early signals

Persistent roughness or scaling

The skin on the ear tip may feel slightly thickened or rough to the touch, with fine scaling that does not resolve. This can resemble dry skin or mild irritation, but it tends to recur in the same spot even after seeming to settle.

Small crusts that reform

A crust or scab may appear, fall off or be scratched away, and then reappear in the same location. The cycle of crusting and shedding can continue for weeks, and the area beneath may look pink or raw.

Localised redness or pink patches

A patch of skin on the ear margin may appear pinker than the surrounding tissue, sometimes with a slightly shiny or taut surface. This redness may come and go initially, but over time it tends to become more constant.

Bleeding with minor contact

The affected area may bleed easily when the cat shakes its head, scratches, or when the ear is gently touched. The bleeding is often minor but recurs readily, and the tissue may seem fragile or prone to breaking down.

Later signals

Open sores or ulcers

The skin may break down into an open sore that does not heal, often with irregular edges and a moist or raw surface. The ulcer may gradually enlarge or deepen, and secondary infection can cause odour or discharge.

Thickened or nodular tissue

The affected area may become noticeably thickened, raised, or nodular, sometimes with a cauliflower-like texture. The normal shape of the ear tip may be distorted, and the tissue can feel firm or irregular beneath the surface.

Loss of ear-tip architecture

As the tumour progresses, the edge of the pinna may become eroded or deformed, with tissue loss that alters the silhouette of the ear. In some cases, the tip may curl or contract as healthy tissue is replaced by abnormal growth.

Click to read about the biological mechanisms

How this is usually investigated

The investigation typically begins with a detailed history of when the changes were first noticed, how they have progressed, and the cat's lifestyle and sun exposure. Physical examination of the ears follows, noting the location, appearance, and extent of any abnormal tissue. Where the pattern suggests squamous cell carcinoma, tissue sampling is usually required to confirm the diagnosis and rule out other conditions that may appear similar. Additional imaging or tests may be considered to assess the extent of involvement and whether the tumour has spread beyond the ear.

Physical examination

Purpose: The veterinary surgeon inspects the pinna for crusting, ulceration, thickening, bleeding, or tissue loss, and palpates the area to assess the texture and depth of any lesions. The surrounding skin, lymph nodes, and other ear structures are also examined to understand the extent of involvement.
Considerations: Physical examination can reveal the pattern and location of changes, but it cannot distinguish squamous cell carcinoma from other conditions that cause similar signs, such as chronic inflammation or other types of tumour. Tissue sampling is needed for a definitive diagnosis.

Fine-needle aspiration or biopsy

Purpose: A sample of cells or tissue is collected from the abnormal area, either by inserting a fine needle to draw out cells or by removing a small piece of tissue with a scalpel or punch tool. The sample is then examined under a microscope by a veterinary pathologist to identify the cell type and confirm whether cancer is present.
Considerations: Fine-needle aspiration can be performed quickly and with minimal restraint, but it may not always yield enough cells for a clear diagnosis, particularly if the lesion is heavily crusted or inflamed. Biopsy provides more tissue and a clearer architectural picture, though it requires local anaesthesia or sedation and leaves a small wound that needs to heal.

Imaging of the skull and chest

Purpose: Radiographs or CT scans of the skull can show whether the tumour has eroded into underlying bone or cartilage. Chest radiographs are used to check for spread to the lungs, which is uncommon in early cases but becomes more relevant if the tumour is extensive or has been present for a long time.
Considerations: Imaging is not always part of the initial work-up, particularly if the lesion is small and confined to the ear tip. It becomes more useful when planning surgery or when the extent of local invasion needs to be understood. Chest imaging may not detect very small metastases, and a clear scan does not rule out future spread.

Lymph node assessment

Purpose: The lymph nodes that drain the ear, particularly those under the jaw and at the base of the skull, are palpated and sometimes sampled with a fine needle to check for cancer cells that may have spread from the primary tumour.
Considerations: Enlarged lymph nodes can indicate spread, but they may also be enlarged due to inflammation or infection unrelated to the tumour. Normal-sized nodes do not guarantee that no spread has occurred, as early metastasis may not cause detectable enlargement.

Staging investigations

Purpose: In cases where the tumour is large or there is concern about spread, additional tests such as advanced imaging or blood work may be considered to assess the overall health of the cat and the extent of disease. These tests help inform decisions about which management approaches are practical.
Considerations: Not all cats require extensive staging, particularly if the tumour is small and the plan is to remove it surgically. Staging becomes more relevant when the tumour is advanced or when systemic treatment is being considered, though it adds time and cost to the process.

Options & trade-offs

Management of squamous cell carcinoma of the pinna usually involves removing or controlling the tumour in the ear, and in some cases addressing the risk of recurrence or spread. The approach taken depends on the size and location of the tumour, how much of the ear is affected, the cat's overall health, and what the owner finds practical and acceptable. Different combinations of surgery, other local treatments, and supportive care may be discussed, each with its own set of considerations.

Surgical removal

The affected portion of the pinna is removed under general anaesthesia, with the surgeon aiming to take out the tumour along with a margin of normal tissue to reduce the chance of leaving abnormal cells behind. In many cases this involves removing part or all of the ear flap, depending on how much tissue is involved. The remaining ear is sutured closed, and the wound is managed as it heals over the following weeks.

Trade-offs: Surgery can be curative if the tumour is caught early and fully excised, and many cats tolerate ear surgery well with little impact on hearing or balance. However, if the tumour has spread into bone or lymph nodes, surgery alone may not be sufficient, and recurrence can occur if margins are incomplete. The procedure requires anaesthesia, which carries some risk, particularly in older cats or those with other health conditions.

Cryotherapy

Abnormal tissue is frozen using a probe cooled with liquid nitrogen, causing the cells to die and slough away over subsequent days to weeks. This approach can be used for small, superficial lesions or as an additional treatment after surgery to address any remaining abnormal tissue at the margins. The procedure is typically performed under sedation or general anaesthesia.

Trade-offs: Cryotherapy avoids the need for surgical excision in some cases and can be repeated if needed, but it does not provide tissue for histopathology to confirm complete removal, making it harder to know whether all abnormal cells have been addressed. It tends to work less well for larger or deeper tumours, and the frozen tissue can be uncomfortable as it heals.

Radiation therapy

High-energy beams are directed at the tumour to damage the DNA of cancer cells and inhibit their growth. Radiation is usually delivered in multiple sessions over several weeks, requiring repeated anaesthesia or sedation. It can be used as the primary treatment if surgery is not practical, or after surgery if the margins are incomplete or the tumour has characteristics that suggest a higher risk of recurrence.

Trade-offs: Radiation can control tumours that are difficult to remove completely with surgery, and it may preserve more of the ear structure than surgical excision. However, it requires access to a specialist centre, multiple visits, and carries costs that can be substantial. Side effects such as skin irritation, hair loss, and delayed healing in the treated area are common, though they are often manageable.

Topical or intralesional chemotherapy

Chemotherapy drugs are applied directly to the tumour or injected into it, aiming to kill cancer cells locally without the systemic side effects of oral or intravenous chemotherapy. This approach is sometimes used for very small or early lesions, or as part of a combination strategy alongside other treatments.

Trade-offs: Local chemotherapy can be less invasive than surgery or radiation, and it may be an option for cats who are poor candidates for anaesthesia. However, it tends to be less effective for larger or more advanced tumours, and multiple treatments are usually needed. There is limited published data on long-term outcomes compared to surgery or radiation.

Sun protection and monitoring

In cases where the tumour is very early or the cat is not a candidate for active treatment, efforts may focus on reducing further UV exposure by keeping the cat indoors during peak sunlight hours, applying pet-safe sunscreen to the ears, or using protective clothing. Regular monitoring allows the owner and veterinary team to track any progression and adjust the approach if the lesion changes.

Trade-offs: Sun protection can slow progression and may prevent new lesions from developing, but it does not reverse existing damage or eliminate a tumour that is already established. This approach is less likely to be sufficient on its own if the lesion is already ulcerated or growing actively, and it requires consistent daily management from the owner.

Common misconceptions

Misconception:

"If the cat stays indoors now, the tumour will stop growing."

Reality:

Reducing sun exposure can help prevent further UV damage and may lower the risk of new lesions developing, but it does not reverse the cellular changes that have already occurred in existing tumours. Squamous cell carcinoma arises from accumulated damage over time, and once abnormal cells are established, they tend to continue dividing regardless of future sun exposure. Indoor living is a useful part of management, but it does not replace treatment for an existing tumour.

Misconception:

"Squamous cell carcinoma of the ear always spreads quickly to other parts of the body."

Reality:

Squamous cell carcinoma of the pinna tends to grow locally and invade surrounding tissue rather than spreading rapidly to distant organs. Spread to lymph nodes or lungs can occur, particularly in advanced cases or if the tumour has been present for a long time, but many cats are diagnosed and treated before this happens. The behaviour of the tumour can vary, and early intervention often improves the chances of controlling it locally.

Misconception:

"If the ear looks better after a scab falls off, the problem has resolved."

Reality:

Squamous cell carcinoma often presents as crusting or scabbing that appears to improve temporarily, only to return or worsen over time. The underlying abnormal cells remain active even when the surface looks less inflamed, and the pattern of recurrence is one of the features that distinguishes this condition from simple wounds or infections. Persistent or recurring changes in the same area warrant investigation, even if they seem to heal intermittently.

Related conditions

Squamous Cell Carcinoma of the Nasal Planum

Squamous cell carcinoma of the nasal planum arises through the same process of sun-related damage in pale, unpigmented tissue, and cats with white ear tips often have white noses as well, meaning both sites may be at risk in the same individual.

Squamous Cell Carcinoma

Squamous cell carcinoma of the pinna is one specific presentation of squamous cell carcinoma, a cancer that can develop in various sun-exposed or mucosal sites; understanding the general behaviour of this tumour type can help orient you to what may unfold at the ear.

Mosquito Bite Hypersensitivity in Cats

Mosquito bite hypersensitivity can cause recurring crusted sores and redness on the ear tips of cats, and because the appearance can overlap with early changes seen in squamous cell carcinoma, biopsy is sometimes needed to distinguish the two.

Eosinophilic Plaque in Cats

Eosinophilic plaque can occasionally appear on the pinna as a raised, moist, inflamed area, and while the underlying process differs from squamous cell carcinoma, the persistent and sometimes ulcerated appearance may prompt investigation to clarify which condition is present.

Otitis Externa in Cats

Otitis externa can cause redness, crusting, and discharge around the ear canal opening, and when these signs extend onto the pinna or persist despite treatment, squamous cell carcinoma may be considered as part of the diagnostic picture.

If your cat has been diagnosed with squamous cell carcinoma of the pinna, or if you are noticing persistent changes in the ears that have not resolved, it may be useful to explore the broader context of sun-related skin damage and how it unfolds over time in pale-eared cats. Understanding the links between UV exposure, cumulative cellular damage, and the conditions that can arise in older animals may help frame conversations with your veterinary team about management and prevention in other areas. The questions that matter most often centre on what is practical for your household, what your cat will tolerate, and how the approach can be adjusted as the situation becomes clearer.