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

• Salivary Gland Sialolipoma

What is Sialolipoma 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. Sialolipoma is a rare and recently discovered histological variant of lipoma. It is well-circumscribed and may resemble a lipoma
• Sialolipoma of Salivary Gland is an uncommon tumor that is observed in both the major and minor salivary glands. These tumors can be aggressive and sometimes exhibit an unpredictable behavior
• Salivary Gland Sialolipomas may be found in children and adults. The cause of formation of this tumor is unknown, and no risk factors have been clearly established
• Most tumors are solitary in nature, small, and asymptomatic. The diagnosis of Sialolipoma of Salivary Gland is generally challenging, since it is a very rare form of lipoma
• No treatment is required in most cases for small-sized tumors; though a complete surgical excision may be performed, if required. The prognosis of Sialolipoma of Salivary Gland is excellent; recurrences, if any, are rare and no malignant transformations are recorded

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

• Sialolipoma of Salivary Gland can occur at any age (average age 60 years). The tumor has been reported in newborns to adults about 80 years of age; some congenital cases are also reported
• When the minor salivary glands are involved, most cases are almost only seen in adults
• Both males and females are affected; a slight predilection for females is observed, when the minor glands are involved
• No racial or ethnic preference is noted

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

• No risk factors are evident for Sialolipoma of Salivary Gland in most of the cases

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 Sialolipoma of Salivary Gland? (Etiology)

The exact cause of formation of Sialolipoma of Salivary Gland formation is unknown. However, some of the factors that have been occasionally associated with lipoma, in general, 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 Sialolipoma of Salivary Gland?

The signs and symptoms of Sialolipoma of Salivary Gland include:

• The presence of a slow-growing, well-circumscribed lump
• The skin over the mass is intact; the mass is usually moveable under the skin
• Usually the mass is small (average size is 2 cm), but if the tumor masses grow, it may give rise to cosmetic issues. A size range of 1-7 cm is observed
• Most lipomas affect the major salivary glands; the parotid gland is involved in most of the cases (77% of the cases), followed by the submandibular gland
• Tumors in the oral cavity affecting the minor salivary glands are found in the hard and soft palate (over 40% of the cases, when minor glands are affected)
• Other locations include the inner cheeks, tongue, floor of the mouth, lower lips, etc.
• The major and minor salivary glands are involved almost evenly
• Facial nerve involvement may be seen in some cases (about 15%)

The symptoms are seen for a long duration; sometimes, even for over 10 years.

How is Sialolipoma of Salivary Gland Diagnosed?

Sialolipoma of Salivary Gland is 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: A differential diagnosis would include pleomorphic adenoma, lipoadenoma, and lipomatosis.

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 Sialolipoma of Salivary Gland?

Complications due to Sialolipoma of Salivary Gland could include:

• Recurrence of the tumor after surgery is very rare
• 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 Sialolipoma of Salivary Gland Treated?

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

• In most of the individuals, no treatment is necessary
• Complete surgical excision of Sialolipoma is the treatment of choice, if individuals have significant signs and symptoms
• A superficial or total parotidectomy may be considered in some cases, when the parotid gland is involved. A surgical removal of the lesion is usually curative
• 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 Sialolipoma of Salivary Gland be Prevented?

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

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

The prognosis of Sialolipoma of Salivary Gland is typically excellent through complete excision of the tumor, since it is benign.

Additional and Relevant Useful Information for Sialolipoma of Salivary Gland:

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