How Vets Diagnose Tumors in Dogs
One way your veterinarian cannot diagnose a tumor is by looking at or feeling it. Frequently, clients want a veterinarians opinion on a mass on their dog but then do not approve diagnostics, perhaps because of cost. Watching a mass to see if it changes or bothers your dog is generally a bad idea, as these are not necessarily signs that a mass is benign.
Your veterinarian can have an idea of what they think a mass is but will not be able to give you a definitive diagnosis without sampling. General lab work can often point toward an organ system that needs to be examined closer but rarely provides a confirmed diagnosis of cancer.
Sampling a tumor is often the best way to diagnose a tumor. The larger the sample, the more accurate the diagnosis will be. Tumor samples can be obtained with a procedure called a fine needle aspirate. During this procedure, a small needle is used to remove a small group of cells from a mass. This procedure can frequently be performed at the same appointment and is minimally invasive.
The downside of a fine needle aspirate is that your sample may not be fully representative of the type of tumor being sampled, and the veterinarian cannot get any information about the layout of the cells, which can help with diagnosis.
Tumor samples can also be obtained with a biopsy. A biopsy can be excisional (the entire tumor) or incisional (a small portion of the tumor). A biopsy will typically require general anesthesia or heavy sedation but can provide more information to help with diagnosis and can sometimes remove the tumor completely.
Biopsies can sometimes be achieved externally but more often are performed surgically when the veterinarian performs an exploratory surgery.
Endoscopy can be used to collect samples as well, similar to a colonoscopy in people. Bladder tumors can be sampled via a urinary catheter or with a routine urinalysis.
Internal tumors are sampled in similar ways but with more complicated methods. Tumors in the abdomen (liver, spleen, kidney, bladder, etc.) can be sampled with a fine needle aspirate that is guided by ultrasound.
Different types of cancer have different treatments. The treatment recommended for a dog’s tumor depends on several factors:
Treatment options include surgical removal, radiation, immunotherapy, and chemotherapy. Several herbal remedies have also been used successfully to help either with the symptoms of a tumor or with its growth. Even changes in diet can help with cancer treatment in dogs.
These tumors come from hair follicle sheath cells and are generally solitary lesions. They can be found on the head, tail, and limbs in canines of older than five years. They are cystic or solid, elevated, round, and well-defined. They can ulcerate and sometimes lose their hair. A biopsy is necessary as well as a microscopic exam. Veterinarians prefer to surgically remove the tumor.
These tumors come from the cells that produce melanin known as melanocytes. The various pigments in a canine’s skin are a result of the melanin that is produced by these melanocytes. The tumors found in the skin are typically benign, but tumors in other areas of the body like the nail bed or oral cavity may be malignant and metastatic. Melanoma tumors are often found on the trunk and face. An examination under the microscope will reveal cells that consist of brown to block granules. The ideal treatment is surgical removal.
These tumors come from the macrophase/monocyte system and can be spread during mating or any other type of close contact. They are generally located on the external genitalia as well as the face. The masses are similar in appearance to cauliflower, and they are solitary or multiple, ulcerated, and friable. The identity of the tumor can be identified under the microscope, and the treatment consists of surgical removal, radiation and/or chemotherapy.
This tumor is a growth that consists of mature fat cells, or lipocytes. It is generally a soft, well-circumscribed, subcutaneous, fluctuant mass that is found over the sternum, chest, abdomen, and upper part of the limbs. Generally, these tumors are found in older females who have been spayed. They can occur as a single mass or as multiple masses. Some of them are infiltrative, which means that they have the ability to penetrate the deeper body tissues; however, most of the tumors are located just beneath the skin. To diagnosis these tumors, a sample of the tumor needs to be examined under the microscope, which determines whether mature lipocytes are present. Surgical removal is generally necessary to treat lipomas. However, depending on the size and location of the tumor, it may be recommended by the dog’s veterinarian to simply leave the lipoma alone. If it is recommended to go the surgical route, it is ideal to remove the lipoma while it is still small.
The cutaneous papilloma in dogs is benign and of non-viral origin. This tumor is more common in older canines. This tumor is a whitish-gray color and is shaped similar to that of a cauliflower. They are generally located on the head, feet, and eyelids. As a general rule, a single cutaneous papilloma can be surgical removed and it is curative.
#3: Ceruminous Gland Adenoma
This particular type of tumor comes from the ceruminous (earwax) cell glands in the ear canal anal. Typically, these tumors are small stalked masses. They are generally located near the eardrum. The symptoms are very similar to that of chronic ear infections. The tumor cells must be examined under a microscope to diagnose ceruminous gland adenomas. Treatment will involve resectioning the complete ear canal, and chemotherapy and radiation are often necessary.