Salivary gland tumors are rare and account for 3% of all head and neck tumors(1).
About 2-7% of pleomorphic adenomas undergo malignant transformation(1).
Tumors of salivary glands are relatively rare accounting for only 3% of all head and neck tumors. Most of these tumors are benign and are found in the parotid glands (approximately 85%) followed by submandibular glands and minor salivary glands and then rarely in sublingual glands (only about 1%). About 75-80% of these tumors are benign in nature of which pleomorphic adenoma is the most common variant. It constitutes approximately 60-70% of all parotid tumors. They are painless, slow-growing, movable, firm, solid mass found beneath the skin or mucosa. When cystic transformation takes place they become soft instead of firm, which is rare(1),(2).
What Happens To Untreated Parotid Tumors?
As discussed already pleomorphic adenoma is the most common tumor of the parotid gland. They have a propensity for malignant transformation in about 2-7% of the cases. They are more commonly found on the right side than the left side and in females more than in males with a ratio of 2:1. It may be found in any age group, even children, but most prevalent in the fifth to sixth decade of life. When left untreated they may grow in size to several centimeters and kilograms in weight. They become giant but are painless mass that is irregular and nodular mass stretching the overlying skin. Malignant transformation is seen in longstanding untreated cases of pleomorphic adenoma(1).
Since these tumors are slow-growing, if their size suddenly increases in a short duration and they show symptoms of pain, ulceration, bleeding, purulence, and deep-tissue invasion, malignancy can be suspected. Usually, these tumors are left untreated due to patients’ negligence or fear of surgery. However, they should not be left untreated for longer periods due to their capacity of malignant transformation, though the risk is low(1).
There is a correlation between the length of untreated pleomorphic adenoma and malignant transformation known as carcinoma ex pleomorphic adenoma. Pathologically, malignancies can be of three types, including benign metastasizing pleomorphic adenoma, carcinoma in pleomorphic adenoma, and carcinosarcoma. Apart from a longstanding history of pleomorphic adenoma, an increased chance of malignant transformation is also seen in the advancing age of the patient, multiple recurrences, size of the tumor, and history of rapid growth with pain and ulcerations, and location of the tumor. The risk of malignancy increases from 1.5% that present for less than 5 years to 9.5% after more than 15 years. These tumors when found in the deep lobe may expand intraorally into the para pharyngeal space and may affect speech and swallowing(1), (3).
When To Visit A Doctor For Parotid Tumor?
Most of the benign and malignant tumors present as a painless mass. Some malignant tumors can cause pain, ulcerations, bleeding, numbness, causalgia, paresthesias, and loss of motor function due to facial nerve paralysis. Generally, benign tumors are slow-growing, but if rapid growth and associated symptoms of pain and ulceration are noted then that should be alarming. The patient should immediately visit a doctor and get himself/herself examined thoroughly(1), (2).
The doctor will examine the mass, ask for complete medical history and history of the mass, and order imaging studies (ultrasound, X-ray, CT scan, MRI, PET scan) as per his/her suspicion and fine-needle aspiration cytology to differentiate a benign tumor from a malignant one(1), (2).
Both malignant and benign tumors require complete surgical excision of the tumor. Additionally, malignant tumor patients may need excision of regional or parotid lymph nodes and post-surgical radiation therapy, if indicated. If the tumor is in the deep lobe total parotidectomy may be indicated. All surgeries require the preservation of the facial nerve. Chemotherapy has not been found effective in the treatment of salivary gland tumors(1), (2).
Early diagnosis and surgical excision are key to manage salivary gland tumors.
- What are Parotid Tumors or Parotid Mass: Causes, Symptoms, Treatments, Prognosis, Complications
- What Is The Most Common Parotid Tumor & How Do You Know If You Have It?
- What Percentage Of Parotid Tumors Are Malignant & Its Etiology?
- Can A Parotid Tumor Cause Ear Pain & Are They Hereditary?
- Can Benign Parotid Tumors Become Malignant & How Big Are Tumors?
- What Is The Best Treatment For Parotid Tumor & Coping Methods For It?