When Must Tumors in Dogs be Removed?

Tumors in dogs can be scary, especially when you don't know whether they are cancerous or not. However, there are many different kinds of tumors, so it's important to seek a veterinary opinion right away. Early detection can be vital to the successful treatment of cancerous tumors, but non-cancerous or benign tumors may not need treatment at all.

Recognizing Tumors in Dogs

Sometimes a lump or bump looks like a tumor, but isn't one at all. That suspicious growth could be a cyst, an ingrown hair follicle or a blood blister. While these sorts of growths may not have a serious impact on your dog's health, they may make him uncomfortable. If you or your vet suspect that a growth is causing your dog pain or discomfort, have it removed.


Lipomas are fatty deposits that grow just under the skin or, sometimes, deep within the muscles. They are soft and rounded, and generally do not cause your dog any pain. Most of the time, lipoma tumors in dogs grow to a certain size and then stop. Removal of such tumors isn't strictly necessary, though you may choose to do so if the lipoma grows large enough to impede your dog's movement.

Sometimes, in rare cases, lipomas can become malignant and spread throughout your dog's body.

Malignant and Benign Tumors

Cancerous tumors fall into two categories: malignant and benign. Malignant tumors can metastasize and spread throughout your dog's body. Benign tumors remain in their place of origin, though they can continue to grow to huge proportions if not removed.

Malignant tumors can result in deadly cancer due to their tendency to spread throughout the body. Even benign tumors can cause a problem if they grow large enough to become inoperable.

Deciding to Remove Tumors in Dogs

Your vet will no doubt use one of these four common methods when diagnosing your dog's tumor:

  • Impression smears involve looking at cells from the tumor under a microscope to determine whether they are cancerous, malignant or benign.
  • A needle biopsy allows your vet to remove cells from the tumor with a needle; this is easier, cheaper and less time consuming than removing the entire tumor for biopsy purposes.
  • CT scans are usually used to determine if tumors have spread to your dog's internal organs.
  • Radiography or x-rays are also used to look for tumors in your dog's internal organs.

If your vet finds that the tumor is cancerous and malignant, have it removed right away. If the tumor is cancerous and benign, you may not need to have it removed; keep an eye on it, and if it begins to grow too large, have it removed. You don't want such a tumor to impede your dog's movement, or grow so large that it can't be removed.

If your dog's tumor is a lipoma, you may also choose to remove it if it grows too large.