Polymorphous adenocarcinoma is a rare type of salivary gland cancer that usually occurs in small glands distributed throughout your mouth. The primary treatments are surgery and radiation therapy.
Polymorphous adenocarcinoma — previously known as polymorphous low grade adenocarcinoma — tends to be a slow-growing cancer that rarely spreads to other tissues.
Many people don’t have any noticeable symptoms when they receive their diagnosis.
The most common treatments for polymorphous adenocarcinoma are surgery and radiation therapy. Radiation therapy is usually only necessary if there’s a high risk your cancer may reoccur.
Like essentially all cancers, the outlook for polymorphous adenocarcinoma tends to be better the earlier it’s diagnosed and treated.
Keep reading to learn more about polymorphous adenocarcinoma, including symptoms, causes, and treatment.
Polymorphous adenocarcinoma tends to grow slowly. Most people don’t have symptoms when they’re initially diagnosed. Swelling inside your mouth is the most common symptom.
The most common location for polymorphous adenocarcinoma is in the roof of your mouth, but it can also occur in other places such as the:
- inner lips
- floor of your mouth
- edges of your tongue
Other potential symptoms of salivary cancers can include:
- facial numbness
- weakness in facial muscles
- numbness in part of your face
- pain in your:
- face
- jaw
- neck
How aggressive is polymorphous adenocarcinoma?
Polymorphous adenocarcinoma has low metastatic (growth) potential, meaning it rarely spreads to distant body parts. Because of its slow growth, doctors can often successfully remove the tumor with surgery.
Polymorphous adenocarcinoma is a rare salivary gland cancer that usually occurs in the minor salivary glands. It makes up about 3% of head and neck tumors.
Doctors don’t know exactly why some people develop polymorphous adenocarcinoma. Like other cancers, it develops when genetic changes in your cells cause them to replicate out of control.
PAC is most common in people in their 50s or 60s. It affects females about twice as often as males.
Salivary gland cancer risk factors
- smoking, which is associated with an increased risk of
Warthin tumors but not other types of tumors - radiation exposure
- infections with some types of viruses, such as human papillomavirus (HPV)
- possibly HIV infection
- possibly a diet low in vegetables and high in animal fat
- possibly heavy cellphone use for parotid gland tumors, although current research is inconclusive
Some workplace exposures, such as nickel alloy dust or silica dust, may be linked to a higher risk of salivary cancer, but the link isn’t still certain. Other people at risk might include people who work in:
- asbestos mining
- plumbing
- rubber products manufacturing
- some types of woodworking
People often receive a diagnosis of salivary gland cancer after they develop swelling and visit their primary healthcare professional.
Initial tests for salivary gland cancer often include:
- a review of your personal and family medical history
- a review of your symptoms
- a physical exam with a complete head and neck exam
If your primary healthcare professional thinks you need further tests, they may refer you to a specialist called an ear, nose, and throat doctor. They may perform or order additional tests such as:
- Indirect pharyngoscopy and laryngoscopy: In this test, a doctor uses small mirrors to look at the back of your throat, the base of your tongue, and your voice box.
- Direct pharyngoscopy and laryngoscopy: For this test, a doctor will insert a thin, flexible tube with a camera into your mouth or nose to assess areas that aren’t easy to see with mirrors.
- Imaging: A doctor might also use imaging tests such as:
Not all salivary gland tumors are cancerous. A biopsy of your salivary gland is necessary to find out whether a tumor is cancerous and to differentiate it from other types of salivary gland cancer.
Types of biopsy you might receive include:
- Fine needle aspiration biopsy: Fine needle aspiration involves taking a small amount of cells and fluid from a tumor with a needle.
- Core needle biopsy: A core needle biopsy involves using a hollow needle to get a section of suspicious tissue and test it for cancer.
- Incisional biopsy: An incisional biopsy involves using a knife to cut out a tiny piece of the tumor.
- Surgery: Surgery involves removing the entire tissue sample. Your doctor might request it if they suspect cancer.
The main treatments for polymorphous adenocarcinoma are
Surgery may involve removing the tumor and surrounding tissue or removing this tissue and some surrounding bone tissue. Removal of your neck lymph node is generally only necessary if there’s evidence that it’s spread.
Radiation therapy is generally only necessary at a high risk of having cancer reoccurrence. Your doctor might recommend radiation therapy if there are still signs of cancer cells at the edges of the tissue surgically removed. This is known as positive surgical margins.
The outlook for polymorphous adenocarcinoma tends to be good since it rarely spreads to distant tissues. A 2019 study found that the 5-year disease-specific survival is about 98%, and the 10-year disease-specific rate is about 94%.
About 15% of people have reoccurrence after surgical removal. Relapse usually occurs 5 to 7 years later.
Survival rate for all salivary cancers
Doctors often use 5-year relative survival rates to report the outcome of a cancer. This statistic measures how likely a person with the cancer is to be alive 5 years later compared to a person without the cancer.
The 5-year relative survival rates of all salivary cancers in the United States from 2014–2020 based on
| Stage | Survival |
|---|---|
| localized | 95.2% |
| regional | 68.5% |
| distant | 33.2% |
| all stages | 75.4% |
Polymorphous adenocarcinoma is a rare salivary gland cancer that usually develops in one of hundreds of small salivary glands throughout your mouth. It tends to progress slowly and rarely spreads to other areas.
Doctors can often successfully treat polymorphous adenocarcinoma with surgery. If there’s a high risk that the cancer might return, they may recommend radiation therapy after surgery.