Bone Cancer in Cats: Symptoms, Diagnosis, and Treatment

Common Types of Cat Bone Cancer

Also known as osteosarcoma, bone cancer is a common diagnosis in felines. Tumors, unfortunately, come in a variety of sizes, and the placement of a cancerous tumor in cats can be almost anywhere. Adding to the wide variation of bone cancer, there are also two different types of bone tumors.

As you will learn from the vet, your cat will have either a primary tumor or a secondary tumor. A primary tumor is a mass of cancerous cells that form in the bone themselves, whereas a secondary tumor grows somewhere near or around the bone instead of in the bone directly. Usually, secondary tumors will arise in bone marrow.

Even though bone cancer is a serious matter, it is not as dangerous as other types of feline cancers, like cell carcinoma. A cell carcinoma tumor forms in the skin of our feline friends, and it creates far more causes for concern than feline bone cancer. Let’s take a closer look at the primary tumors because there are actually four different types of primary tumors in cats!

The Four Kinds of Primary Tumors that Cats Can Develop

As mentioned, within the category of primary tumors in cat bones, there are four different kinds of tumors. All of these tumors grow in the bones of cats, but what sets them apart is the part of the bone that they originate from.

These four types of primary bone tumors in cats are…

  • Chondrosarcoma
  • Fibrosarcoma
  • Hemangiosarcoma
  • Osteosarcoma

Dogs are far more likely to develop primary bone tumors than cats, though it is still possible for cats to have primary tumors despite being very unlikely. When they do grow from the bones of cats, these primary tumors are not aggressive in most cases.

Feline bone tumors tend to be more benign than anything, which is good news for cats. Of the four primary bone tumors in cats, the most frequently diagnosed tumor is osteosarcoma. The other three types of primary tumors are not as common in cats. Let’s take a look at these four primary tumors more closely!


Like other types of primary tumors, chondrosarcoma is very rare in cats. Our feline friends are not at a high risk for chondrosarcoma, though it might still develop in unusual circumstances. This type of sarcoma grows from cartilage, so it’s likely you’ll find a primary chondrosarcoma tumor in the connective cartilage between a bone and a joint.


Fibrosarcoma is one of the more common types of bone cancer. It takes a lot for fibrosarcoma cells to metastasize and spread via the lymph nodes to other parts of a cat’s body, but even so, the fibrosarcoma cells are very aggressive at their site of origin. This is what professionals refer to as a locally aggressive type of cancer.

The exact cause of fibrosarcoma is still up in the air because researchers believe there could be multiple contributing factors of feline fibrosarcoma. However, a commonality among cats that are diagnosed with fibrosarcoma tumors is vaccination.



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