Sebaceous Cysts in Cats

What is a sebaceous cyst?

Sebaceous cysts (epidermal inclusion cysts) are benign tumours of the skin. They are the most common surface tumour found in cats and are composed of a thick, cheesy, yellow substance known as sebum, which is a secretion of the sebaceous gland comprised of fat and cellular debris, which lubricates and protects the skin.

Sebum originates from the sebaceous glands, which are tiny glands located within the hair follicle. Sebaceous cysts occur when the follicle becomes blocked, causing a build-up of sebum to occur. Left untreated, sebaceous cysts can become infected and therefore while the cysts themselves are harmless, they should be seen by a veterinarian.

There is no breed, age or sex predilection.

Symptoms

Smooth, soft fluid-filled lumps which may have a blue hue to them. Cysts can grow up to 1-2 inches in diameter. The most common areas to develop cysts are the head, neck, and trunk.

Occasionally they will rupture, oozing a thick paste-like yellow-grey substance.

Diagnosis

The veterinarian can make a tentative diagnosis based on physical examination but diagnostics will be recommended.

Diagnostic workup:

  • Punch biopsy: A small amount of tissue from the cyst is removed and sent to a testing laboratory for signs of cancer.
  • Ultrasound: A non-invasive test that uses high-frequency sound waves to identify the contents of the cyst.

Treatment

Do not attempt to squeeze cysts yourself, if you notice any growths on your cat, seek veterinary attention. Some veterinarians will recommend a wait and see approach, you will be asked to regularly monitor the cyst for signs of growth or infection. If treatment is indicated, the veterinarian will surgically excise the cyst either by electrocautery or cryotherapy, however, there is a risk that new cysts will grow. Antibiotics will be prescribed if a secondary bacterial infection is present.