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

• RMS of Salivary Gland
• Salivary Gland Rhabdomyosarcoma

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

• A rhabdomyosarcoma (RMS) is a very uncommon, high-grade malignant ‘skeletal muscle’ tumor of the soft tissues. RMS tumors are poorly-defined, fleshy, expanding masses that form deep within the body tissues, or below the skin surface
• Rhabdomyosarcoma of Salivary Gland is an extremely uncommon high-grade malignancy that mostly involves the major salivary gland (specifically the parotid gland). The tumor is usually diagnosed in children and frequently in advanced progression stage
• The cause of formation of this salivary gland tumor is believed to be due to genetic abnormalities. No definitive risk factors are observed, but rhabdomyosarcomas are generally known to be associated with the use of illegal drugs (cocaine), exposure to carcinogens, and certain genetic disorders
• The presenting signs and symptoms of Rhabdomyosarcoma of Salivary Gland may include a slowly-growing facial lump and pain while eating/chewing. Occasionally, anemia and neurological symptoms may be observed
• Rhabdomyosarcoma of Salivary Gland is treated using a combination of surgery, chemotherapy, and radiation therapy. The prognosis of the condition is generally guarded

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

• Rhabdomyosarcoma of Salivary Gland is a very rare malignancy that usually affects young children and adolescents; most cases are detected before age 10
• Both male and female genders are affected
• No ethnic or racial preference has been observed

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

Currently, no specific risk factors are noted for the development of Rhabdomyosarcoma of Salivary Gland. In general, rhabdomyosarcomas may be associated with the following factors:

• Family history of the condition has been observed, though very rarely
• Use of drugs, such as cocaine or marijuana, by the parent mother
• Carcinogens (some have been found on mice and certain types of fish)
• Beckwith-Wiedemann syndrome
• Costello syndrome
• Li-Fraumeni syndrome
• Neurofibromatosis (type) 1
• Noonan syndrome

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 Rhabdomyosarcoma of Salivary Gland? (Etiology)

The cause of Rhabdomyosarcoma of Salivary Gland may be due to inherited genetic defects or de novo (sporadic and spontaneous) genetic mutations.

Currently, studies indicate defects in the following genes:

• Alveolar rhabdomyosarcoma:
  • PAX3-FKHR causing chromosomal translocation abnormality namely t(2;13)(q35;q14)
  • PAX7-FKHR causing chromosomal translocation abnormality namely t(1;13)(p36;q14)
• Spindle cell rhabdomyosarcoma:
  • SRF-NCOA2 causing chromosomal translocation abnormality namely t(6;8)(p21;q13)
  • TEAD-NCOA2 causing chromosomal translocation abnormality namely t(8;11)(q13;p15)
• Embryonal rhabdomyosarcoma:
  • Currently, studies indicate defects in CDKN1C, H19, HOTS, and IGF2 genes
  • Additionally, certain chromosomal anomalies have been observed

Note: The alveolar, spindle cell, and embryonal variant of rhabdomyosarcoma have been observed in the salivary gland (parotid gland).

The above genetic abnormalities can be detected using molecular studies, which may play a significant role in identifying the tumor type, and in some cases, helping the healthcare provider take appropriate treatment decisions.

• 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 Rhabdomyosarcoma of Salivary Gland?

Rhabdomyosarcoma 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
• 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
• Involvement of the parotid glands are seen in a vast majority of the cases; the tumor may be present as a mass in the gland
• Extremely rarely, the other major salivary glands (submandibular and sublingual) may be involved
• Pain may be felt on the ear, jaw, or upper cheeks
• Anemia may be observed, in some cases
• 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 Rhabdomyosarcoma of Salivary Gland Diagnosed?

A diagnosis of Rhabdomyosarcoma 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
• Genetic testing and analysis, for detecting any chromosomal aberration

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 Rhabdomyosarcoma of Salivary Gland?

Complications of Rhabdomyosarcoma 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
• Tumor metastasis to local and distant sites: The lung, bone, and bone marrow are the commonly involved organs
• 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 Rhabdomyosarcoma of Salivary Gland Treated?

The treatment of Rhabdomyosarcoma of Salivary Gland involves a combination of surgery, chemotherapy, and radiation therapy. The treatment may also depend upon the stage, overall health, age, and subtype of the tumor.

The treatment measures for Salivary Gland Rhabdomyosarcoma 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 RMS origin
• Following surgery, radiation therapy is usually provided for tumors of the head and neck region
• 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
• 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 with regular screening and check-ups are important, to watch for recurrence and any metastatic behavior

How can Rhabdomyosarcoma of Salivary Gland be Prevented?

• Current medical research has not established a method of preventing the formation of Rhabdomyosarcoma of Salivary Gland
• Genetic counseling and testing: If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• 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 Rhabdomyosarcoma of Salivary Gland? (Outcomes/Resolutions)

• The prognosis of Rhabdomyosarcoma of Salivary Gland is generally guarded. Most individuals are reported to die due to advanced disease and/or metastasis, caused by late diagnosis of the condition
• Factors that favor better outcomes include age of the child less than 2 years, small tumor sizes, and tumor type/variant (alveolar type has the poorest outcome)
• 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 Rhabdomyosarcoma 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/