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Salivary Gland Adenocarcinoma in Dogs

What Is Salivary Gland Adenocarcinoma in Dogs?

Salivary gland adenocarcinoma in dogs is a type of cancer that affects the salivary glands, of which dogs have four pairs located in the jaw or neck region. These glands produce saliva, which is essential for various oral functions. Among the types of cancer that can affect these glands, adenocarcinoma is the most prevalent and aggressive.

Dogs possess four pairs of salivary glands: the zygomatic glands below the eye, the mandibular glands behind the jawbone where the neck meets the jaw, the sublingual glands under the tongue, and the parotid glands around the base of the ear. Adenocarcinoma most commonly affects the parotid gland, although other glands can also be affected.

Furthermore, there are accessory salivary glands scattered throughout the mouth, found in the lips, cheeks, and palate. Salivary gland adenocarcinoma develops when the cells lining these glands undergo uncontrolled growth, leading to the formation of a tumor. Early diagnosis and prompt veterinary treatment are crucial in managing this aggressive form of cancer in dogs.

Symptoms and Types

Symptoms of salivary gland adenocarcinoma in dogs vary depending on the size and location of the tumor. Common symptoms to watch for include:

  • Halitosis (bad breath)
  • Excessive drooling
  • Difficulty swallowing
  • Alterations in the dog’s voice, such as changes in barking patterns
  • Noticeable, painless swelling near a salivary gland
  • Bulging of one eye
  • Swelling of the lips, cheeks, around the ear/upper neck area, or beneath the tongue

These symptoms can indicate the presence of adenocarcinoma in the salivary glands and should prompt a visit to the veterinarian for evaluation and diagnosis.


The exact causes of salivary gland adenocarcinoma in dogs remain unknown. While many cancers can be attributed to environmental or genetic factors, there are currently no identified genetic or environmental causes specifically linked to salivary gland adenocarcinomas. Research continues to explore the underlying factors contributing to the development of this type of cancer in dogs.


When veterinarians suspect salivary gland adenocarcinoma in dogs, they initiate a diagnostic process. This typically involves examining the dog’s health records and discussing observed symptoms with the owner, which may include difficulty swallowing or eating, bad breath, or other relevant indications.

Fine Needle Biopsy

Your veterinarian might opt for a fine needle biopsy to gather cells from the tumor for microscopic examination. In this procedure, a very fine needle is used to extract a small sample of cells from the tumor. Subsequently, these cells undergo microscopic analysis to distinguish whether they are cancerous or related to infection or inflammation.


If abnormal cells are detected, your veterinarian might suggest X-rays of the skull and neck to detect any bone changes near the affected salivary gland.

Surgical Biopsy

In a surgical biopsy, your veterinarian surgically removes either the entire tumor or a portion of it. The excised tissue is then forwarded to a specialized medical professional known as a pathologist for examination and diagnosis.


The primary treatment for salivary gland adenocarcinoma involves surgical removal of the tumor. However, before proceeding with surgery, your veterinarian may conduct tests to assess whether the cancer has spread to other areas of your dog’s body.

The process of cancer spreading is referred to as metastasis, and cancers are categorized into stages based on the extent of their spread. Adenocarcinomas commonly metastasize to nearby lymph nodes, and in some cases, to the lungs. Treatment approaches may vary depending on whether the cancer has metastasized beyond the original gland.

Upon determining the cancer’s stage, your veterinarian may recommend further diagnostic tests to formulate an appropriate treatment plan. Additional assessments may include:

  • Complete blood chemistry
  • Urinalysis
  • Chest X-rays and/or abdominal ultrasound

Given the aggressive nature of salivary gland adenocarcinoma, your veterinarian might also propose a CT scan or MRI to assess the surrounding glandular area.

Radiation Therapy

Adenocarcinoma is frequently highly aggressive and can extend to adjacent areas of the face, such as major blood vessels and nerves, or even the lungs. In cases where complete tumor removal isn’t feasible, your veterinarian might suggest radiation therapy. Additionally, radiation therapy is employed to address tumors situated in locations where surgical removal is impractical due to their positioning.


If examinations reveal that the cancer has metastasized to other parts of the body, your veterinarian might recommend chemotherapy as part of the treatment plan.

Recovery and Management

Following surgery, your dog’s recovery entails resting comfortably at home. Your veterinarian may prescribe medications to alleviate pain and inflammation, as well as antibiotics to stave off infection. Regular follow-up appointments with your veterinarian are essential, and depending on the diagnosis, your dog may require additional treatment such as radiation therapy.

Salivary Gland Adenocarcinoma in Dogs FAQs

What is the survival rate for salivary gland adenocarcinoma in dogs?

The combination of surgery and radiation therapy typically extends a dog’s lifespan. However, if the tumor is not entirely removed or if radiation therapy proves ineffective, the tumor may regrow at its original site. Without any treatment, dogs diagnosed with adenocarcinoma typically survive for approximately 1.5 years on average.

How aggressive is salivary gland adenocarcinoma in dogs?

Salivary gland adenocarcinomas can be highly aggressive and frequently spread to neighboring areas of the body. Due to the salivary glands’ location, tumors may affect major nerves and blood vessels, making complete surgical removal challenging.

What do salivary gland adenocarcinomas look like?

Salivary gland adenocarcinomas are often not directly visible due to their location. However, some owners may observe firm, non-painful swelling at the base of one ear, in the upper neck near the jawline, or bulging of one eye.

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