Lump (Incisive Papilla) on the Roof of a Cat’s Mouth

What is the lump on the roof of my cat’s mouth?

Have you noticed a bump on the roof of your cat’s mouth between the incisors? This small done-shaped projection is the incisive papilla and is present in all cats, humans, dogs, horses and many other mammals.

What does the incisive papilla do?

Also known as the palatine papilla, the incisive papilla (frequently mislabelled the vomeronasal organ) connects the oral cavity with the vomeronasal organ via the incisive duct which contains fluid-filled incisive (nasopalatine) canals.

The vomeronasal organ is a taste-smell organ that is used to identify pheromones from other cats. Pheromones in glandular secretions and urine advertise important information such as territorial boundaries, dominance and reproductive status.

Most cat owners will be familiar with the flehmen response that occurs when the cat encounters a pheromone. He or she will open the mouth and curl the upper lips to transfer the pheromones into the mouth. Once inside, the tongue flicks the scent upwards to the incisive papilla and transfers it to the vomeronasal organ via the incisive ducts.

Flehmen response. medveda/Shutterstock

Other causes of lumps in a cat’s mouth

While the incisive papilla is a completely normal part of the cat’s anatomy, other lumps and bumps in the mouth are not. If you notice any lumps or bumps in your cat’s mouth, schedule an appointment with a veterinarian. Common causes include dental abscesses and tumours. A dental abscess is a puss-filled pocket most often associated with trauma, gum disease or feline odontoclastic resorptive lesions.

Occasionally the incisive papilla itself can become swollen due to malocclusion, trauma or if the cat eats something hot. In most cases, this is temporary and should resolve, as always, speak to your ca’s veterinarian if it remains swollen for longer than a few days.


The incisive papilla is a normal part of the cat’s anatomy and plays an important role in the detection of feline pheromones which relay important inter-species information.