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

• Lipomatous Salivary Gland Tumor
• Parotid Gland Lipoma
• Salivary Gland Lipoma

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

• Lipomas are very common benign tumors of fat tissues (adipose tissues). They can occur in almost any part of the body
• Lipoma of Salivary Gland is an uncommon tumor that is generally observed in the major salivary gland. It usually affects adults over the age of 40 years
• The cause of formation of Salivary Gland Lipoma is unknown, and no risk factors have been clearly established. However, some studies inform that a positive family history, radiation to the head and neck area, obesity, and corticosteroid therapy may be occasionally causative
• Most tumors are solitary in nature, small, and asymptomatic. Lipoma of Salivary Gland typically arises from the parotid gland. It is usually seen on one side of the face, but may be rarely multiple and bilateral
• Multiple tumor masses are known to arise in some cases. The diagnosis of Lipoma of Salivary Gland is generally challenging, since it is very rare. However, the diagnosis can be confirmed through a tissue biopsy
• No treatment is required in most cases; though a complete surgical excision may be performed, if required. The prognosis of Lipoma of Salivary Gland is usually excellent

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

• Adults over 40 years are generally affected by Lipoma of Salivary Gland, though they can occur at any age (including in infants and children)
• Both males and females are affected; though, a slight predilection for males is observed
• No racial or ethnic preference is noted

Currently, only a few cases of Salivary Gland Lipoma have been reported worldwide. Since the tumor is uncommon, there is only limited information available in the medical literature.

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

No risk factors are evident for Lipoma of Salivary Gland in most the cases.

• In some individuals, having a family history of lipoma may increase the risk
• The presence of multiple lipomas (known as lipomatosis) may be associated with certain conditions such as Madelung disease, radiation therapy to the head and neck region, HIV infection, abnormal steroid/hormone use, etc.

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 Lipoma of Salivary Gland? (Etiology)

The exact cause and mechanism of Lipoma of Salivary Gland formation is unknown. However, some of the factors that have been occasionally associated with lipoma formation include:

• Radiation therapy to the region
• Lifestyle factors including obesity and diabetes
• Insulin injections
• Steroid therapy
• Positive family history
• Endocrine disorder
• Trauma or injury to the region

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

The signs and symptoms of Lipoma of Salivary Gland include:

• The presence of a slow-growing lump on the jaw, by the side of the face. The lump is typically painless, but can be occasionally painful
• The skin over the mass is intact; the mass is usually moveable under the skin
• Usually the mass is small (less than 3-4 cm in size), but if the masses grow, it may give rise to cosmetic issues
• Most lipomas affect the major salivary glands; the parotid gland is involved in many of the cases, followed by the submandibular gland. It is estimated that about 3-4% of the parotid gland tumors are lipomas
• Rarely, multiple lipomas have been observed

How is Lipoma of Salivary Gland Diagnosed?

Lipoma of Salivary Gland are diagnosed using the following tools:

• Complete physical examination and a thorough evaluation of individual’s medical history
• 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 may show 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

Note: An important differential diagnosis is a liposarcoma, which is a malignant tumor.

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 Lipoma of Salivary Gland?

Complications due to Lipoma of Salivary Gland could include:

• Occasionally, recurrence of the tumor after surgery (if surgery does not entirely remove the tumor)
• The tumors may become large, causing cosmetic issues
• Discomfort while speaking, eating, etc.
• Surgery to remove the tumor mass may result in facial nerve palsy (surgical complication)
• Post-surgical wound infection

How is Lipoma of Salivary Gland Treated?

The treatment measures for Lipoma of Salivary Gland may include the following:

• In most of the individuals, no treatment is necessary
• Complete surgical excision of Lipoma is the treatment of choice, if the individuals have the following signs and symptoms:
  • The tumor is infected, with or without foul-smelling pus discharge
  • Sudden increase in size of the lipoma
  • If the tumor that was painless, suddenly becomes painful
  • If the tumor on the face causes cosmetic issues
  • If the tumor affects the normal functioning of the jaw
• Post-operative care is important: One must maintain minimum activity levels, until the surgical wound heals
• Follow-up following surgery/treatment is recommended

How can Lipoma of Salivary Gland be Prevented?

Current medical research has not established a method of preventing Lipoma of Salivary Gland formation.

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

• The prognosis of Lipoma of Salivary Gland is excellent through complete excision of the fat tissue tumor, since it is benign
• Infrequently, the tumor may recur, if it is incompletely removed

Additional and Relevant Useful Information for Lipoma of Salivary Gland:

• There are many subtypes of lipomas, but all are benign tumors
• Sometimes, lipomas can occur in the muscles, when it is called intra-muscular lipoma. They can also occur in the bones, called bone lipomas