Squamous cell carcinoma (SCC) is a common and aggressive type of skin cancer in cats, primarily affecting areas with little or no fur. Understanding the classification and various types of feline SCC is crucial for early detection and effective treatment. This article provides a detailed overview of the different types of feline squamous cell carcinoma, their characteristics, and the importance of recognizing these variations for optimal care and management.

What is Feline Squamous Cell Carcinoma?

Feline squamous cell carcinoma is a malignant tumor that arises from the squamous cells, which are found in the outermost layers of the skin and mucous membranes. This cancer is particularly prevalent in white or light-colored cats and typically develops in areas with minimal hair, such as the ears, eyelids, and nose, due to increased exposure to ultraviolet (UV) radiation.

Classification of Feline Squamous Cell Carcinoma

Feline SCC can be classified based on its location, histopathological features, and the degree of invasiveness. Understanding these classifications helps veterinarians determine the best treatment approach.

1. Cutaneous Squamous Cell Carcinoma

Cutaneous SCC is the most common form of SCC in cats, occurring on the skin’s surface. It typically affects areas with high sun exposure and minimal fur coverage, such as:

• Ears: The tips of the ears are particularly susceptible to SCC due to their exposure to UV light. Lesions may appear as red, inflamed areas that progress to ulcers and crusting.
• Nose: The bridge of the nose and the nostrils can develop SCC, presenting as sores or crusty lesions.
• Eyelids: SCC can affect the eyelids, causing swelling, redness, and ulceration.

2. Oral Squamous Cell Carcinoma

Oral SCC occurs inside the mouth, affecting the gums, tongue, or palate. It is one of the most aggressive forms of SCC and can be challenging to treat due to its location. Symptoms include:

• Oral Lesions: Ulcers or masses in the mouth that may bleed or cause difficulty eating.
• Drooling: Excessive drooling, often tinged with blood.
• Bad Breath: Foul-smelling breath due to necrotic tissue.

3. Subungual Squamous Cell Carcinoma

Subungual SCC develops under the claws, leading to:

• Swelling: Swelling and inflammation around the claw bed.
• Lameness: Limping or reluctance to walk due to pain.
• Claw Loss: The affected claw may become loose or fall off.

Histopathological Features

Histopathological examination of SCC involves analyzing tissue samples under a microscope to determine the tumor’s characteristics. Key features include:

• Cell Differentiation: The degree to which cancer cells resemble normal squamous cells. Poorly differentiated cells indicate a more aggressive tumor.
• Invasion Depth: The extent to which the tumor has invaded underlying tissues, affecting treatment options and prognosis.

Treatment and Prognosis

The treatment and prognosis of feline SCC depend on the tumor’s type, location, and stage at diagnosis. Common treatments include:

• Surgery: Surgical removal of the tumor with wide margins is the primary treatment for SCC. Early-stage tumors have a better prognosis.
• Radiation Therapy: Often used for tumors in difficult-to-operate areas or as an adjunct to surgery to prevent recurrence.
• Cryotherapy: Freezing small, superficial tumors with liquid nitrogen.
• Chemotherapy: Typically used for advanced or metastatic SCC, although its effectiveness can vary.

Understanding the classification and types of feline squamous cell carcinoma is essential for early detection and effective treatment. By recognizing the different forms of SCC and their characteristics, cat owners and veterinarians can work together to ensure the best possible outcomes for affected cats. Regular monitoring and preventive measures, such as limiting sun exposure, can also help reduce the risk of SCC in cats.