Last reviewed by Dr. Raj MD on January 12th, 2022.
What is Pleomorphic Adenoma?
This is one of the most common types of non-cancerous tumor, also known as a benign neoplasm, a person can have and is found in your salivary glands. Your salivary glands are located around and in your throat and mouth and their purpose is to secrete saliva into your mouth in order to keep it moist, begin your digestion process, help maintain good oral hygiene, and to help lubricate and bind the food you are eating. This type of non-cancerous, or benign, tumor is also called a mixed tumor, which means that the tissue origin that makes up this type of tumor comes from different types of cells. A pleomorphic adenoma will usually grow slowly over time and is a painless hard, mobile, solitary mass. This type of tumor will usually occur in adults between the ages of forty-five and sixty. It is also diagnosed more in females than in men.
You will find most of the pleomorphic adenomas develop in your parotid gland, which is located just below your ear and near your upper teeth and produces a watery secretion, which is half of your daytime saliva, through your salivary ducts which in turn drain your saliva. The parotid gland is the largest of the salivary glands and has two lobes. One is the superficial lobe and the other is the deep lobe separated by your facial nerve. There are also a few incidences of it occurring in your submandibular glands which is located under your tongue and produces a part mucous, part transparent secretion. Although the pleomorphic adenoma is normally benign it does have the potential to become cancerous, also referred to as malignant.
Symptoms of Pleomorphic Adenoma
In the early stages a pleomorphic adenoma is usually painless but as they start to grow larger these tumors can start to cause complication in your ears or mouth. If they start to cause complications in your mouth you may see symptoms such as:
- Having difficulty chewing
- Having a hoarse throat
- Having difficulty swallowing
If they start to cause complication in your ears you may see symptoms such as:
- An interference with your speech
- An interference with the nerves that control your facial muscles
If the pleomorphic adenoma becomes malignant it will usually start to grow rapidly and cause pain. It could also become life-threatening.
What are the Causes of Pleomorphic Adenoma?
There are many different factors and causes of developing a pleomorphic adenoma which can include:
- Chain smoking
- Radiation exposure
- Blockage of your salivary ducts which in turn will inhibit the drainage of saliva from the glands and is the most common cause of developing pleomorphic adenoma.
In order to correctly diagnosis a pleomorphic adenoma your physician may schedule you to have an outpatient procedure called a biopsy of the cells to determine which type of tumor it is and if it is benign or malignant. To help the physician with the size and location of the pleomorphic adenoma they order a CT scan, MRI, or ultrasound tests. In addition a CT scan can also help show your physician whether or not the tumor has intruded upon any surrounding tissues.
When your physician finds an adenoma they will commonly have them tested by fine needle aspiration (FNA) to see if it is pleomorphic adenoma. It is a histopathologic technique and because of its safety in diagnosing this type of tumor this is why this method is usually chosen by physicians. The test is performed by a physician who specializes in the study of tissues in order to determine the cause of a disease called a pathologist. The pathologist will use a syringe and needle to withdraw a sample of the tumor and then the tissue samples are processed in a lab and read by the pathologist who performed the test.
Treatment for Pleomorphic Adenoma
How pleomorphic adenomas are treated depends on the size, where it is located, and at which stage the tumor is. Another big consideration is if the benign tumor has become malignant. Some choose to leave them untreated but if not treated some of the pleomorphic adenoma can experience malignant changes because of them recurrence. These cancerous transformations are known as carcinoma ex pleomorphic adenoma or malignant mixed tumor.
Surgery is the most common form of treatment for pleomorphic adenoma. If the pleomorphic adenoma is in your parotid gland it can be a delicate surgery due to the closeness to your facial nerves and the potential for the surgery to cause damage to these facial nerves. During the surgery the part of the organ that is affected by the pleomorphic adenoma is removed referred to as surgical resection. If it is in your parotid gland it is normally done by the removal of the superficial lobe of your parotid gland called superficial parotidectomy. This type of surgery is generally done under general anesthesia. It can take three to four hours to have the surgery and is done by making an incision near your ear on the neck and will heal with minimal scarring.
Many times in order to try and prevent recurrence the surgeon will do a total parotidectomy which is when both lobes and some of the surround tissue are removed. The reason that some of the surrounding tissue has to be removed is because the pleomorphic adenoma is known to have finger-like extensions that grow into the surrounding tissue. This is the type of surgery that can cause facial nerve damage.
If the pleomorphic adenoma is found to be malignant the surgery is sometimes followed up by radiation treatment. Forty-four percent who have complete tumor removal the prognosis is good. Even though you have surgery to remove the pleomorphic adenoma it unfortunately has a fairly high rate of recurring again with a mortality rate of approximately eighty-seven percent. The original pleomorphic adenoma is a single mass any that recur can be multinodular.