Lipomas and Sebaceous Adenomas

Odds are, any older dog I examine will have a growth (or two, or three, or four) within the skin and subcutaneous tissue — the layer just beneath the skin.

The good news is, the majority of these masses are benign. It’s that small population of malignant tumors that keeps us on our toes. They’re the reason it’s important that your veterinarian inspect any newly discovered lumps and bumps. In general, the smaller a cancerous growth is at the time of diagnosis, the better the outcome.

Sebaceous adenomas

Sebaceous adenomas are the most common benign skin tumors in middle-aged and older dogs. They form from oil-producing sebaceous glands within the skin. They’re typically pea-sized or smaller and round or wart-like in appearance. My 16-year-old dog has more than a half dozen scattered about his body.

Because they’re benign, most sebaceous adenomas require no treatment whatsoever. For dogs prone to them, surgically removing these small tumors can transform a dog into a patchwork quilt! Consider surgery when:

• A sebaceous adenoma recurrently bleeds or becomes infected because of self-trauma (the dog licks or chews at them), or because it gets nicked by the groomer’s clippers.

• A sebaceous adenomas secretes sebum galore and creates an oil slick on the dog’s hair coat. No fun!

• A sebaceous adenomas is just downright ugly, like warty little aliens poking through the hair coat.

If surgery is warranted, most sebaceous adenomas can be removed using local rather than general anesthesia.

Lipomas

Lipomas arise from fat (lipid) cells and their favorite sites to set up housekeeping are in the subcutaneous tissue (just beneath the skin surface) of the axillary regions (armpits) and alongside the chest and abdomen. Some lipomas develop internally within the chest or abdominal cavity. Rarely does a dog develop only one lipoma. They tend to grow in multiples, and I’ve examined individual dogs with more lipomas than I could count.

Most of these benign, slow-growing tumors require no treatment other than at-home monitoring. You can even track measurements on a regular basis. Here are some reasons to consider surgery:

• A steadily enlarging lipoma has the potential to interfere with mobility. The armpit is a classic spot for this.

• The lipoma is growing rapidly and/or changing in appearance.

• Your veterinarian is suspicious that your dog’s tumor might be a liposarcoma, the malignant black sheep of the fatty tumor family.

The key to lipomas is monitoring their growth and removing them before they become so large that they become difficult to remove. On multiple occasions I’ve thought, “Wow, look at that dog attached to a lipoma!”

Has your older dog developed any lipomas or sebaceous adenomas?

Best wishes to you and your four-legged family members for abundant good health,

Dr. Nancy