CONDITION

Squamous Cell Carcinoma

Why this matters now

Squamous cell carcinoma is a malignant skin cancer commonly affecting cats, with particular predilection for areas with minimal fur cover and light pigmentation. The ear tips, nose, and eyelids of white or light-coloured cats are most frequently affected due to sun exposure. The tumour is locally aggressive, gradually destroying surrounding tissue. Unlike some other feline cancers, squamous cell carcinoma tends to spread locally rather than to distant organs, though advanced cases can metastasise.

The condition often begins with subtle changes—crusting, scabbing, or non-healing wounds on the ears or nose. These early lesions may be mistaken for fight wounds or minor irritation. Without intervention, the tumour progressively invades deeper tissues, causing significant tissue destruction. Ear tip lesions may erode through the pinna. Nasal lesions can extend into the nasal cavity, causing breathing difficulty and disfigurement. Early recognition offers the best chance of successful treatment.

Signals & patterns

Early signals

Crusting or scabbing on ear tips

Persistent crusty lesions that do not heal with time or topical treatment.

Non-healing wound on the nose

A sore or ulcer on the nasal planum that recurs or fails to resolve.

Redness and thickening of skin

Pre-cancerous changes may appear as chronic inflammation of sun-exposed areas.

Changes around the eyes

Crusting or ulceration of the eyelid margins in light-coloured cats.

Later signals

Tissue erosion

Progressive destruction of ear or nose tissue becomes apparent as the tumour advances.

Bleeding from affected areas

Ulcerated tumours may bleed, sometimes significantly.

Difficulty breathing

Nasal tumours extending into the nasal passages cause obstruction and noisy breathing.

Facial deformity

Advanced nasal or periocular tumours cause visible distortion of facial features.

Click to read about the biological mechanisms

How this is usually investigated

Diagnosis involves examining suspicious lesions and obtaining tissue samples. Staging assesses local extent and checks for spread.

Physical examination

Purpose: To assess the lesion and check regional lymph nodes
Considerations: Examination determines tumour size, location, and involvement of surrounding structures. Enlarged lymph nodes may indicate spread.

Biopsy

Purpose: To confirm the diagnosis through microscopic examination
Considerations: A small tissue sample is examined by a pathologist. May be obtained under sedation or anaesthesia.

Fine needle aspirate of lymph nodes

Purpose: To check whether cancer has spread to regional lymph nodes
Considerations: Cytology can detect tumour cells in lymph nodes, though false negatives occur.

CT scan

Purpose: To assess the extent of nasal or advanced tumours
Considerations: Provides detailed imaging of tumour invasion into bone and surrounding structures. Helps plan surgery or radiation.

Chest radiographs

Purpose: To look for lung metastases
Considerations: Distant spread is uncommon with early lesions but should be assessed with advanced tumours.

Options & trade-offs

Treatment options depend on tumour location, size, and extent. Early lesions often have good outcomes; advanced tumours are more challenging.

Surgical excision

Removing the tumour with margins of healthy tissue.

Trade-offs: Curative for many early lesions. Ear tip amputation (pinnectomy) is well tolerated and often curative for ear tumours. Nasal planum removal is more disfiguring but can control disease.

Cryotherapy

Freezing small superficial tumours with liquid nitrogen.

Trade-offs: Suitable for very early or pre-cancerous lesions. Less invasive than surgery. May require multiple treatments. Not appropriate for invasive tumours.

Radiation therapy

Using radiation to kill cancer cells.

Trade-offs: Effective for tumours where surgery is difficult or incomplete. Requires multiple treatment sessions under anaesthesia. Side effects can occur in irradiated tissue.

Photodynamic therapy

A specialised treatment combining a light-sensitive drug with specific light wavelengths.

Trade-offs: Available at some referral centres. Suitable for superficial tumours. Cats must be kept away from bright light during treatment period.

Sun avoidance

Keeping cats indoors during peak UV hours and using pet-safe sunscreen.

Trade-offs: Important for prevention and may slow progression of early changes. Does not treat established tumours but helps prevent new ones.

Common misconceptions

Misconception:

"Indoor cats cannot get sun-related skin cancer"

Reality:

Cats that sunbathe by windows still receive UV exposure. Glass blocks some but not all UV radiation. Indoor cats with light colouring can develop squamous cell carcinoma.

Misconception:

"A crusty ear tip will heal on its own"

Reality:

Persistent crusty lesions on ear tips or nose of white cats should be examined. Early squamous cell carcinoma mimics minor wounds but does not resolve and gradually worsens.

Misconception:

"Surgery will leave my cat disfigured and unable to cope"

Reality:

Cats adapt remarkably well to ear tip removal. Nasal surgery, whilst changing appearance, is generally well tolerated. Cats prioritise comfort over aesthetics.

Being aware that white or light-coloured cats face higher risk helps target monitoring efforts. Checking ear tips and nose regularly for changes allows early detection. Understanding that early lesions are often curable encourages prompt investigation of suspicious changes. Taking steps to reduce sun exposure may help prevent disease development.

Last reviewed: 24 April 2026 · Dr Alastair Greenway MRCVS