What are the other Names for this Condition? (Also known as/Synonyms)

• Oncocytic Adenoma of Salivary Gland
• Oxophilic Adenoma of Salivary Gland
• Salivary Gland Oncocytoma

What is Oncocytoma of Salivary Gland? (Definition/Background Information)

• Oncocytoma of Salivary Gland is a rare and benign tumor typically arising from the parotid glands (major salivary gland). A majority of them are seen in middle-age and older adults
• Generally, the cause of formation of Oncocytomas of Salivary Gland is unknown; however, a past history of radiation exposure to the head and neck region may be a contributory factor, in some cases
• Most tumors are solitary, small, and asymptomatic. Oncocytoma of Salivary Gland typically presents as a well-defined, painless mucosal mass. It is more often seen in the major than minor salivary gland
• The diagnosis of Oncocytoma of Salivary Gland can be confirmed through a tissue biopsy. The treatment of choice is a complete surgical removal of the tumor
• The prognosis of Oncocytoma of Salivary Gland is generally excellent in most cases, since it is a benign tumor. Extremely rarely, tumor recurrences following surgery has been reported

Who gets Oncocytoma of Salivary Gland? (Age and Sex Distribution)

• Oncocytomas of Salivary Gland are uncommon and constitute around 1% of all salivary gland tumors
• It is typically present in adults in the age range 50-80 years (mean age 58 years)
• Both males and females are affected. Some studies show a preference for females
• The tumor can affect all races and ethnic groups

What are the Risk Factors for Oncocytoma of Salivary Gland? (Predisposing Factors)

The risk factors for Oncocytomas of Salivary Glands may include:

• A history of radiation exposure is observed in about 1 in 5 individuals:
  • The exposure may have occurred as part of radiation therapy to the head and neck (or upper trunk) region
  • Or, due to longstanding occupational exposure (often for 5 years or more)

Note: The affected individuals, without prior radiation exposure, are generally observed to be around 20 years older than the subset of individuals with clearly-established radiation exposure history.

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Oncocytoma of Salivary Gland? (Etiology)

• Currently, the cause of formation of Oncocytomas of Salivary Gland is unknown
• In about 20% of the affected individuals, radiation exposure due to occupational factors, or radiation administered for therapeutic purposes is observed

What are the Signs and Symptoms of Oncocytoma of Salivary Gland?

The signs and symptoms of Oncocytoma of Salivary Gland may include:

• Presence of a well-formed, firm tumor mass in the mouth that presents no pain
• Often, the tumor is slow-growing and develops over many months and years
• In a majority, the tumor affects the major salivary glands; i.e., the parotid gland is involved in about 80-85% of the cases. The next most common site is the submandibular gland
• When the minor salivary glands are involved, the tumor may be seen in the inner cheek lining, the lower lips, hard/soft palate, and in the pharynx
• The tumor size averages about 3-4 cm
• Occasionally, large tumors may cause pain and discomfort

How is Oncocytoma of Salivary Gland Diagnosed?

The following exams and procedures may be used in the diagnosis of Oncocytoma of Salivary Gland:

• Evaluation of the individual’s medical history and a through physical examination
• Plain X-ray of the head and neck region
• Ultrasound scan of the affected salivary gland
• CT or CAT scan with contrast of the head and neck usually shows a well-defined mass. This radiological procedure creates detailed 3-dimensional images of structures inside the scanned region
• MRI scans of head and neck region: A magnetic field is used to create high-quality pictures of certain parts of the body, such as tissues, muscles, nerves, and bones. These high-quality pictures may reveal the presence of the tumor

Although the above modalities can be used to make an initial diagnosis, a tissue biopsy of the tumor is necessary to make a definitive diagnosis to begin treatment. The tissue for diagnosis can be procured in multiple different ways which include:

• Fine needle aspiration (FNA) biopsy of the tumor: A FNA biopsy may not be helpful, because one may not be able to visualize the different morphological areas of the tumor. Hence, a FNA biopsy as a diagnostic tool has certain limitations, and an open surgical biopsy may be recommended.
• Salivary gland core biopsy of the tumor
• Salivary gland open biopsy of the tumor

Tissue biopsy:

• A tissue biopsy of the tumor is performed and sent to a laboratory for a pathological examination. A pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis. Examination of the biopsy under a microscope by a pathologist is considered to be gold standard in arriving at a conclusive diagnosis
• Biopsy specimens are studied initially using Hematoxylin and Eosin staining. The pathologist then decides on additional studies depending on the clinical situation
• Sometimes, the pathologist may perform special studies, which may include immunohistochemical stains, molecular testing, and very rarely, electron microscopic studies to assist in the diagnosis

The differential diagnosis of a Salivary Gland Oncocytoma may include:

• Acinic cell carcinoma
• Clear cell carcinoma
• Warthin tumor
• Metastatic renal cell and thyroid carcinomas
• Mucoepidermoid carcinoma (MEC)

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Oncocytoma of Salivary Gland?

Significant complications due to Oncocytoma of Salivary Gland are generally not noted. In some cases, the following may be observed:

• Discomfort while speaking, eating, etc.
• Some tumors may cause blockage of the nose or airways
• Surgery to remove the tumor mass may result in facial nerve palsy (surgical complication)
• Post-surgical wound infection
• The tumor is known to recur very infrequently following surgical excision
• When it recurs, often multiple tumors are observed; also, the involvement of both salivary glands (bilateral) may be seen. This may cause diagnostic and treatment challenges

How is Oncocytoma of Salivary Gland Treated?

• A complete surgical excision with clear margins is the preferred mode of treatment of Oncocytoma of Salivary Gland. This can result in a cure
• Post-operative care is important: One must maintain minimum activity levels, until the surgical wound heals
• Regular follow-up post-surgery/treatment is recommended

How can Oncocytoma of Salivary Gland be Prevented?

• Current medical research has not established a method of preventing the formation of Oncocytoma of Salivary Glands
• Regular medical screening at periodic intervals following treatment is beneficial

What is the Prognosis of Oncocytoma of Salivary Gland? (Outcomes/Resolutions)

• The prognosis of Oncocytoma of Salivary Gland is generally excellent with surgical intervention and complete removal, since it is a benign tumor. The risk of tumor recurrence following surgery is minimal
• However, recurrent tumors may involve both the parotid or submandibular glands (bilateral involvement). Also, the presence of multiple tumors in the oral cavity may be noted. These factors may adversely affect the overall prognosis

Additional and Relevant Useful Information for Oncocytoma of Salivary Gland:

There are 3 major types of salivary glands and these include the following:

• Parotid glands, found on the sides of the face
• Submandibular glands located at the back of mouth, on both sides of the jaw
• Sublingual glands that are seen under the floor of the mouth

The salivary glands produce saliva that helps in:

• Lubricating the mouth
• Swallowing
• Protects the teeth against bacteria
• Digestion of food