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

• Haemangiopericytoma of Salivary Gland
• HPC of Salivary Gland
• Salivary Gland Hemangiopericytoma

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

• Hemangiopericytoma (HPC) of Salivary Gland is a rare, low-grade malignant tumor of the mesenchyme. The parotid (major salivary) gland is the usual site of involvement. The tumor is mostly diagnosed in adults
• Generally, a malignancy in mesenchymal cells leads to the formation of a sarcoma, and hence, hemangiopericytoma can be termed as a type of soft tissue sarcoma. The mesenchyme are cells that form various components of the body including the connective tissues, lymphatic and circulatory system tissues
• The cause of formation of this salivary gland tumor is believed to be due to genetic abnormalities. No definitive risk factors are observed, but hemangiopericytomas are known to be associated with prolonged exposure to certain chemicals and steroid therapy
• The presenting signs and symptoms of Hemangiopericytoma of Salivary Gland may include a slowly-growing facial lump and pain while eating/chewing. Neurological symptoms, such as facial muscle weakness, may be noted
• The treatment involves a combination treatment of surgery, chemotherapy, and radiation therapy. However, the prognosis of Hemangiopericytoma of Salivary Gland is typically guarded

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

• Hemangiopericytoma of Salivary Gland is a malignancy that usually affects adults
• Both males and females are affected and no preference is noted
• No ethnic or racial preference has been observed
• Even though Salivary Gland Hemangiopericytoma is a very rare tumor, hemangiopericytomas constitute the more common primary sarcomas affecting the salivary glands (after malignant schwannoma and fibrosarcoma)

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

Currently, no specific risk factors are noted for the development of Hemangiopericytoma of Salivary Gland. However, the following factors may be involved in its formation:

• Prolonged chemical exposure
• Steroid therapy
• Trauma to the region

The following general risk factors are noted for salivary gland cancers:

• Exposure to ionizing radiation (which may be from natural or artificial sources)
• Occupations involving woodwork, plumbing, and mining (asbestos)
• Working in manufacturing industry related to certain materials, such as rubber products

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 Hemangiopericytoma of Salivary Gland? (Etiology)

The cause of Hemangiopericytoma of Salivary Gland is not well-established. Certain gene mutations have also been reported in the tumors. Research is being performed to determine how these mutations contribute to the formation of the tumors.

• In general, it is known that cancers form when normal, healthy cells begin transforming into abnormal cells - these cancer cells grow and divide uncontrollably (and lose their ability to die), resulting in the formation of a mass or a tumor
• The transformation of normally healthy cells into cancerous cells may be the result of genetic mutations. Mutations allow the cancer cells to grow and multiply uncontrollably to form new cancer cells
• These tumors can invade nearby tissues and adjoining body organs, and even metastasize and spread to other regions of the body

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

Hemangiopericytoma of Salivary Gland signs and symptoms include:

• Presence of a firm and visible swelling, typically on the side of the face, that is slowly increasing in size
• The tumors are known to be present and grow over long time durations and remain asymptomatic (painless)
• Initially, the overlying skin may not appear inflamed or present changes in texture or color
• As the tumor progress and becomes larger in size, changes in the overlying skin including ulceration may be noted
• Since these tumors have a rich supply of blood vessels, the skin overlaying the tumor is warm to touch. Sometimes, pulsation and an audible sound (bruit) may be noted
• Involvement of the parotid glands are seen in a majority of the cases; the tumor is usually present as a painful mass in the gland
• Malignant tumors may cause neurological signs and symptoms, such as facial muscle weakness and pain, due to facial nerve involvement
• Persistent facial pain at the site of swelling of the tumor; this requires an immediate checkup by a healthcare provider

How is Hemangiopericytoma of Salivary Gland Diagnosed?

A diagnosis of Hemangiopericytoma of Salivary Gland is made using the following tools:

• Complete evaluation of family (medical) history, along with a thorough physical examination
• Plain X-ray of the head and neck
• 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 body
• MRI scans of head and neck: Magnetic resonance imaging (MRI) uses a magnetic field 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 is preferred
• Salivary gland core biopsy of the tumor
• Salivary gland open biopsy of the tumor

Tissue biopsy of the tumor:

• A tissue biopsy of the nodule 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

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 Hemangiopericytoma of Salivary Gland?

Complications of Hemangiopericytoma of Salivary Gland may include:

• Cosmetic concerns (facial disfigurement) and severe emotional stress
• Ulceration and bleeding from the tumor
• Large-sized tumors may compress adjoining tissues and structures resulting in additional complications
• Breathing or swallowing difficulties (if tumor mass obstructs the food pipe or wind pipe)
• Tumor recurrence following surgical treatment is seen in many cases (20-50%). In some cases, the tumors have returned after many decades (after 30 years)
• Tumor metastasis to local and distant sites: The lung and bone is the most commonly involved organ; spread of the tumor to other sites is observed in 11-56% of the cases
• Surgical complications: Surgery to remove the tumor mass may result in facial nerve palsy and gustatory sweating (Frey syndrome)
• Post-surgical wound infection
• Side effects from chemotherapy (such as toxicity), radiation therapy

How is Hemangiopericytoma of Salivary Gland Treated?

The treatment of choice for Salivary Gland Hemangiopericytoma is surgery. The treatment may also depend upon the stage, overall health, age, and subtype of the tumor.

The treatment measures for include the following:

• Wide surgical excision with removal of the entire lesion is the standard treatment mode. A total parotidectomy may be considered if the parotid gland is the primary site of tumor origin
• Following surgery, radiation therapy is usually provided for tumors of the head and neck region. Adjuvant radiation therapy is reported to be generally effective
• When the tumor is at an inaccessible location, or is unsafe for surgical intervention, non-invasive procedures, such as chemotherapy and radiation therapy (using fast neutron-beam), may be considered. The tumor response to adjuvant chemotherapy is unclear
• Recurrent salivary gland tumors are also known to respond better to fast neutron-beam radiation therapy than other treatment modes
• Embolization is used to provide temporary relief from the symptoms, and reduce blood loss during a surgical procedure
• Clinical trial therapies (especially for stage IV disease) including therapeutic drugs, radiation, stem cell transplantation, and monoclonal antibodies, either singly or in combination of various therapies
• Post-operative care is important: A minimum activity level is to be ensured until the surgical wound heals
• Follow-up care (long-term) with regular screening and check-ups are important, to watch for recurrence and any metastatic behavior

How can Hemangiopericytoma of Salivary Gland be Prevented?

• Current medical research has not established a method of preventing the formation of Hemangiopericytoma of Salivary Gland
• Regular medical screening at periodic intervals with blood tests, radiological scans, and physical examinations, are mandatory for those who have been diagnosed with the tumor
• Due to its high metastasizing potential and chances of recurrence, often several years of active follow-up and vigilance is recommended

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

• The prognosis of Hemangiopericytoma of Salivary Gland is generally guarded. Since, these tumors are rare, the exact rate of survival is not known. From among the reported cases, one-third of the patients died within 12 years
• Unfavorable prognostic indicators include advanced disease stage, certain histological features (poorly-differentiated type, higher grade), high cell division rate, and large tumor sizes
• The prognosis of salivary gland cancer, in general, depends upon a set of several factors that include:
  • Stage of tumor: With lower-stage tumors, when the tumor is confined to site of origin, the prognosis is usually excellent with appropriate therapy. In higher-stage tumors, such as tumors with metastasis, the prognosis is poor
  • The size of the tumor: Individuals with small-sized tumors fare better than those with large-sized tumors
  • Overall health of the individual: Individuals with overall excellent health have better prognosis compared with those with poor health
  • Age of the individual: Older individuals generally have poorer prognosis than younger individuals
  • Individuals with bulky disease have a poorer prognosis
  • Involvement of the lymph node can adversely affect the prognosis
  • Involvement of vital organs may complicate the condition
  • The surgical respectability of the tumor (meaning, if the tumor can be removed completely)
  • Whether the tumor is occurring for the first time, or is a recurrent tumor. Recurring tumors have worse prognosis compared to tumors that do not recur
  • Response to treatment of salivary gland cancer: Tumors that respond to treatment have better prognosis compared to tumors that do not respond to treatment
  • Progression of the condition makes the outcome worse
• An early diagnosis and prompt treatment of the tumor generally yields better outcomes than a late diagnosis and delayed treatment
• In general, for all salivary gland malignancies the following may be noted:
  • The recurrence rate is between 40-65%
  • Spread of the tumor (metastasis) is seen in 38-65% of the cases
  • And, the death rate lies between 35-65%; most deaths occurring within 3 years of tumor diagnosis

Additional and Relevant Useful Information for Hemangiopericytoma 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 following article link will help you understand other cancers and benign tumors:

http://www.dovemed.com/diseases-conditions/cancer/