Not Every Lump Under a Cat’s Tongue Is Cancer, Vet Dentist Says

When an older cat starts drooling blood, eating less and struggling to swallow, a growth under the tongue is most often squamous cell carcinoma, an aggressive mouth cancer. But a veterinary dental specialist has reminded colleagues that other, sometimes very treatable, conditions can look much the same. Writing in Veterinary Practice News, Dr. John Lewis of Veterinary Dentistry Specialists in Chadds Ford, Pennsylvania, describes a young cat whose alarming swelling turned out not to be cancer at all.

The case that looked like cancer

The patient was Milo, a one-year-old ragdoll. The mass under his tongue was firm, rough and ulcerated, which is the kind of appearance that raises fears of carcinoma. Milo also had a history of a swollen lower lip. A biopsy, in which a small piece of tissue is examined under a microscope, showed an eosinophilic granuloma instead. This is an inflammatory reaction driven by a type of white blood cell, and it is often linked to allergies.

Because the swelling was so large that the vets worried Milo might injure it with his own teeth, they started steroid treatment while waiting for the lab results. According to Dr. Lewis, the swelling shrank considerably within a week and had nearly disappeared after two weeks. The team suggested Milo see a veterinary dermatologist to look for an allergic trigger. Dr. Lewis called the case a good reminder of how important tissue testing is for reaching a firm diagnosis.

Other causes of swelling under the tongue

The article lists several less common problems that vets should consider:

• Ranulas. These are smooth, soft swellings caused by saliva leaking and collecting after damage to a salivary gland or duct. The name comes from the Latin word for frog, because the swelling resembles a frog’s belly. They are usually not inflamed. Some go away on their own, but surgery to remove the affected glands is often needed.
• Eosinophilic granulomas. Best known as “rodent ulcers” on a cat’s upper lip, they can also appear under the tongue. Some look smooth like a ranula; others look rough like a tumour. They often come with other signs, such as a puffy lower lip.
• String and thread. Linear foreign bodies, such as string that wraps around the thin band of tissue under the tongue, can cause redness and severe swelling. They are most common in young cats but also happen in dogs. Dr. Lewis recalls a 10-year-old dog that chewed the twine inside a golf ball and ended up with it wound around the base of her tongue.
• Granulation tissue. Long-term irritation, for example from a rough tooth surface left by tooth resorption, can lead to a buildup of healing tissue in the area.

He also notes that after some mouth surgeries, swelling from tied-off salivary ducts can mimic a ranula, though these so-called pseudoranulas usually settle within a few days.

What it means for cat owners

The column is written for vets, but the message is useful at home. A lump or swelling under a cat’s tongue is serious and should never be ignored, yet it is not automatically a death sentence. The appearance alone cannot tell cancer from inflammation or a saliva cyst, which is why a biopsy matters before any decision about treatment is made.

Owners who notice drooling, blood in the saliva, reduced appetite, trouble swallowing or visible swelling should book a visit with their veterinarian. A cat with string hanging from its mouth or wrapped under the tongue also needs prompt veterinary care. If your pet may have swallowed something toxic, contact an emergency vet or the ASPCA Animal Poison Control Center.

What remains uncertain

The article is a clinical review built around individual cases, not a study, so it does not say how often these lookalike conditions occur compared with cancer. Dr. Lewis also points to a small 1978 experiment in dogs in which damaging salivary ducts did not produce ranulas, while noting he has seen at least one ranula develop after surgery. For owners, the practical takeaway is simple: get any mouth swelling examined, and ask your vet whether a biopsy is needed to know for sure.

Source: Veterinary Practice News