My Pet has a Lump. Is it Cancer?

That is a good question. A lump or mass can be many things including cancer. It can be a benign mass such as a lipoma (fatty tumor) or adenoma (wart-like growth), a cyst, a hematoma (blood filled pocket), an abscess (infection) or cancer.

If you find a mass at home, mark it with either nail polish or a marker on the hair (especially if it is a small mass) in order that it is easier to find during the exam. We also will want to know how long the mass has been present and if it has changed any since you first found it.

It is possible to obtain a large amount of information about a mass based on physical examination, but ultimately in order to determine whether we have a cancerous situation, we need to run a few tests. The first diagnostic test is called a fine needle aspirate. This is where a small gauge needle (same size that is used to give vaccinations) is inserted into the mass and a small amount of cells are withdrawn for evaluation under the microscope. It can be done on almost all masses that are either on the skin or under the skin. It is usually done without the need for sedation and has few side effects. The slide may be read inhouse by our licensed veterinary technicians who are practiced in this area or sent to our laboratory for a pathologist’s evaluation.

If the fine needle aspirate indicates the presence of cancerous cells or is inconclusive (or if the mass is not accessible for a fine needle aspirate), the next diagnostic step is a biopsy of the mass. In this case your pet will be sedated and the lump removed. It will be sent to a laboratory for analysis. The veterinarian will help to determine the best course of action once the mass has been identified. Most malignant masses are usually best dealt with by excision as the first line of defense and many are cured by this method

One common cancer, called a mast cell tumor, is notorious for having the appearance of almost any other lump and this is one important reason to have all lumps checked with a fine needle aspirate. Mast cell tumors should be removed surgically and biopsied. You cannot tell by feel or sight the difference from a mast cell tumor and any other type of tumor.

Most lumps, however, are benign and require no treatment. In fact, dogs often develop numerous lumps as they get older. But the safest approach is to have any lump evaluated. Early diagnosis and treatment of malignant masses provide the best prognosis for your pet.