Quick answer: A parotid gland oncocytoma is a rare tumor of the salivary gland near the ear. It is usually benign, often slow-growing, and commonly treated with surgery when removal is recommended.

Oncocytoma: Quick Facts for Patients

• Usually benign: Most parotid oncocytomas are not cancer.
• Often painless: They commonly appear as a slow-growing lump near the ear, cheek, or jaw.
• Diagnosis can take time: Imaging and needle biopsy can help, but final diagnosis may require pathology after removal.
• Surgery is common: Complete removal is often curative.
• Follow-up matters: A specialist can recommend monitoring based on the tumor and the patient’s health.

What Is a Parotid Gland Oncocytoma?

An oncocytoma is a tumor made up of epithelial cells called oncocytes. When it develops in the parotid gland—the large salivary gland located in front of and below the ear—it most often appears as a slow-growing, painless lump. These tumors are generally solid, well-defined, and surrounded by a capsule.

Oncocytomas of the parotid gland are a very rare and benign growth. Published medical references describe them as accounting for roughly 1% to 2% of salivary gland tumors, and most salivary gland oncocytomas occur in the parotid gland. Oncocytomas are also called Oxyphillic adenomas or Oncocytic papillary cyst adenomas. 

Is a Parotid Oncocytoma Cancerous?

In the parotid gland, oncocytomas are almost always benign. Malignant oncocytic tumors can occur, but they are very rare and only occur in 1% of the cases. For most patients, an oncocytoma behaves as a slow-growing benign tumor rather than an aggressive cancer.

Because parotid masses can be difficult to diagnose with certainty before removal, a head and neck specialist can help determine the safest next step. Key factors may include:

• How confident the diagnosis is based on imaging, examination, and any biopsy results;
• Whether the mass is growing, painful, or causing symptoms;
• The patient’s age, overall health, and surgical risk;
• The size and location of the tumor, including how close it is to the facial nerve.

Parotid Oncocytoma Symptoms and Warning Signs

Parotid oncocytomas are most often seen in adults over age 50, especially people in their 60s and 70s. These tumors are rare in patients under the age of 50. They usually present as a painless, slow growing masses that can be found anywhere in the parotid gland. These tumors can be bilateral or multicentric, meaning they occur on both sides or in more than one area of the same gland, which occurs approximately 10% of the time.

• Usually slow-growing
• Often painless
• Most commonly found in the parotid gland
• Usually benign
• Can occasionally be bilateral or involve more than one tumor focus

What Causes a Parotid Gland Oncocytoma?

The exact cause of parotid oncocytoma is not fully understood. Some medical studies have found them to be more frequent in women. There is no definite causal factors with the exception of prior radiation exposure to the parotid gland potentially being a cause. Some pathologists also describe oncocytomas as possibly arising from changes or proliferation in normal salivary gland cells as opposed to an actual tumor.

How Parotid Oncocytoma Is Diagnosed

These tumors can be hard to diagnose with imaging tests or a biopsy.  These tumors contain many mitochondria—the parts of cells that produce energy. Because they use a lot of energy, they may appear brighter on a PET scan and can sometimes look like cancer, even when they are not.

Fine needle aspiration, or FNA, may provide helpful information, but oncocytic cells can sometimes resemble other salivary gland tumors under the microscope. Because of this uncertainty, many oncocytomas are diagnosed definitively only after the mass is surgically removed and examined by a pathologist.

Parotid Gland Oncocytoma: Treatment and Recovery

The usual treatment for a parotid oncocytoma is surgical removal. Depending on the size and location of the tumor, this may involve removing the mass along with a portion of the parotid gland while carefully preserving the facial nerve. In many cases, this is done as a partial or superficial parotidectomy.

For most patients, complete removal is curative. Recurrence is uncommon, but the risk can be higher when a tumor is incompletely removed or when there are multiple tumor areas.

Can a Parotid Oncocytoma Be Monitored Instead of Removed?

Observation may be considered in select situations, especially when a confident diagnosis has been made, the tumor is not causing symptoms or cosmetic concerns, and surgery would carry higher-than-usual risk because of age, other health conditions, or tumor location. This decision is individualized and should be made with a specialist familiar with parotid tumors.

If observation is chosen, the follow-up schedule depends on the patient’s overall health, tumor size, symptoms, imaging findings, and whether the mass changes over time. A growing mass, new pain, facial weakness, skin changes, or uncertainty about the diagnosis may prompt a recommendation to move forward with treatment.

Call your doctor promptly if: the lump grows quickly, becomes painful, causes facial weakness, leads to skin changes, or changes in a way that concerns you.

Parotid Oncocytoma Prognosis and Follow-Up Care

The outlook for parotid oncocytoma is excellent when the tumor is completely removed. Recurrence is rare after complete excision. If a new lump appears later, it may represent recurrence, a separate new oncocytoma, or a previously undetected small tumor focus.

After surgery, follow-up often involves periodic physical examinations. If there are no new lumps or concerning symptoms, routine imaging may not be necessary, although each patient’s follow-up plan should be tailored to their situation.

Key Takeaways About Parotid Gland Oncocytoma

• Parotid oncocytoma is a rare salivary gland tumor that is usually benign.
• It commonly appears as a slow-growing, painless lump near the ear or jaw.
• Diagnosis can be difficult before surgery because it can resemble other parotid tumors.
• Surgical removal is the standard treatment for most patients.
• When completely removed, the prognosis is excellent and recurrence is uncommon.

Medical Review and Source Attribution 

This educational information was provided by Kerry D. Olsen, MD, an emeritus consultant and former chair of the Division of Head and Neck Surgery within the Department of Otolaryngology–Head and Neck Surgery at Mayo Clinic in Minnesota, and an emeritus professor of otolaryngology at Mayo Clinic College of Medicine and Science.¹

Reference

1. Mayo Clinic. Kerry D. Olsen, M.D. Accessed September 21, 2026. https://www.mayoclinic.org/biographies/olsen-kerry-d-m-d/bio-20054537

Medical Disclaimer

This information is intended for general education only and should not replace medical advice. Anyone with a parotid mass should speak with an otolaryngologist, head and neck surgeon, or other qualified healthcare professional for diagnosis and treatment recommendations.