Understanding Skin Tumours In Dogs And Cats

Skin and subcutaneous (under-the-skin) tumours are the most common cancers diagnosed in dogs and cats. They can range from relatively benign growths to aggressive malignancies that metastasise quickly. Because the skin is the body’s largest organ, these tumours are obvious to owners, but their behaviour can vary widely, making accurate diagnosis and staging essential.

Common malignant skin and subcutaneous cancers in dogs include mast cell tumours, soft tissue sarcomas, squamous cell carcinoma, and malignant melanoma. In cats, squamous cell carcinoma, fibrosarcoma, and mast cell tumours are the more frequent. While some tumours may appear small and manageable, their biological behaviour can be aggressive, and microscopic spread may already be present at the time of diagnosis.

Skin and subcutaneous tumours usually present as lumps or swellings, but not all masses behave the same way. Some grow slowly and remain localised, while others invade surrounding tissues or metastasise to lymph nodes, lungs, or other organs. 
Clinical evaluation involves:

• Physical exam and fine needle aspirates (FNA) are first-line tools to differentiate between benign and malignant diseases.
• Histopathology (biopsy) is essential for definitive diagnosis and grading.
• Staging tests, including thoracic radiographs, ultrasound, and advanced imaging, are performed to determine the extent of disease.

Early and accurate staging is critical, as the biological behaviour of skin and subcutaneous cancers can differ dramatically even within the same histological type.

This is where PET-CT technology provides a decisive advantage over conventional imaging. A PET-CT scan goes beyond structural detail, showing how tissues function at the metabolic level. For skin and subcutaneous tumours, this offers several key benefits:

• Accurate staging. Detects hidden metastases in lymph nodes, lungs, or distant organs that may not be visible on CT, ultrasound, or radiographs.
• Treatment planning: It differentiates between active tumour tissue and scar tissue, helping surgeons or oncologists define the true margins of disease.
• Monitoring response. The PET-CT scan identifies metabolic changes early, allowing vets to evaluate whether chemotherapy, radiation, or surgery is effective before physical changes occur.
• Prognostic clarity. It provides more accurate information on tumour activity, guiding realistic discussions with owners about outcomes and options.

By combining PET with CT, veterinarians gain metabolic mapping and precise anatomical localisation, ensuring nothing is overlooked.

PET Theranostics provides the gold standard in cancer imaging and diagnostics, offering clarity where conventional methods may leave uncertainty. Every referral remains under the care of the primary vet or specialist, with our role focused on providing actionable insights for case management. We are currently accepting referrals. Pet owners can contact their vet directly and request a referral to Pet Theranostics.