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

• Cardiac Synovial Sarcoma
• Primary Synovial Sarcoma of Heart
• Synovioma of Heart

What is Synovial Sarcoma of Heart? (Definition/Background Information)

• In general, a synovial sarcoma (SS) is a malignant tumor of the connective tissue, involving the tendon sheath and synovial cells of the joints. However, a synovial sarcoma is not confined to the joint locations alone; but, it may occur in soft tissues, all over the body. The main sites are the lower limb joints, followed by the head and neck region
• Synovial Sarcoma of Heart is an extremely rare malignancy of the heart. It is a primary tumor and so it originates within the heart. Hence, it is also known as Primary Cardiac Synovial Sarcoma
• The tumor is mostly found in the atrium (upper chamber of the heart) and pericardium. The tumors can be locally infiltrative and cause obstructive signs and symptoms including chest pain and breathing difficulties
• The tumors are mostly observed in young and middle-aged adults. Currently, there are no identified risk factors or cause for Synovial Sarcoma of Heart, though certain chromosomal translocations have been identified
• The treatment of Synovial Sarcoma of Heart is undertaken through surgery. However, since it is difficult to remove the entire tumor, chemotherapy and/or radiation therapy may be necessary
• The prognosis of Synovial Sarcoma of Heart is generally poor due to the heart function being affected, local invasion, and metastasis of the cancer to various body sites

Who gets Synovial Sarcoma of Heart? (Age and Sex Distribution)

• Synovial Sarcoma of Heart is a very rare soft tissue malignancy of the heart; they constitute approximately 5% of all heart sarcomas
• The tumor occurs mostly in young and middle-aged adults (around 30-50 years); it has also been observed in children and older adults
• Both males and females are affected, though some studies indicate that it occurs more in males (male-female ratio of 3:1)
• No racial or ethnic preference is noted

What are the Risk Factors for Synovial Sarcoma of Heart? (Predisposing Factors)

Currently, no specific risk factors are noted for the development of Synovial Sarcoma of Heart. However, the following factors may be linked to the condition:

• Some reports indicate an association with exposure to asbestos
• Radiation therapy performed for Hodgkin lymphoma

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones 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 Synovial Sarcoma of Heart? (Etiology)

The exact cause and mechanism of formation of Synovial Sarcoma of Heart is unknown. But, it has been proposed that certain chromosomal translocation leading to gene abnormalities, may be the initiator of synovial sarcoma development.

• 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 Synovial Sarcoma of Heart?

The signs and symptoms of Synovial Sarcoma of Heart may include:

• A majority of the tumors are observed in the atrium and pericardium
• Synovial sarcomas are firm, well-circumscribed, and solitary in appearance
• Bulky, large-sized tumors may be seen; these tumors are locally infiltrative
• Chest pain, breathing difficulty, blood in cough, dizziness, and fainting may be present

Small tumors may not present any significant signs and symptoms.

How is Synovial Sarcoma of Heart Diagnosed?

The following tools may be used towards establishing a diagnosis of Synovial Sarcoma of Heart:

• Complete evaluation of family (medical) history, along with a thorough physical examination; including examination of the heart, with special emphasis to signs such as abnormal heart sounds
• Transthoracic echocardiography (TTE): This procedure uses sound waves to create a motion picture of the heart movement
• Electrocardiogram (EKG or ECG): It is used to measure the electrical activity of the heart, to detect arrhythmias
• MRI scan and CT scan of the heart:
• Doppler ultrasound: Sound waves are used to measure the speed and direction of blood flow
• Whole-body PET scan, bone scan of affected region to check for tumor metastasis. This helps with the staging of the tumor
• Tissue biopsy of the tumor:
  • A 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 additional studies, which may include immunohistochemical stains, electron microscopy, and molecular studies to assist in the diagnosis

Note: Due to the rarity of these tumors, it can cause diagnostic challenges during a frozen section biopsy.

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 Synovial Sarcoma of Heart?

Complications due to Synovial Sarcoma of Heart could include:

• Congestive heart failure, depending on the location of the tumor in the heart
• Increased risk for thromboembolism (blood clot obstructing a blood vessel)
• Cardiac tamponade (or fluid in the pericardium) causing low blood pressure, fatigue, anxiety, rapid breathing, and fainting
• Metastasis of the tumor to other sites in the body; any part of the body may be affected
• Recurrence of the tumor after surgery, when the entire tumor is not removed
• Blood loss during invasive treatment methods may be heavy
• Damage of vital nerves, blood vessels, and surrounding structures during surgery
• Side effects from chemotherapy (toxicity), radiation therapy

How is Synovial Sarcoma of Heart Treated?

The treatment measures for Synovial Sarcoma of Heart may include a combination of the following:

• Surgery: Complete excision where possible is attempted; though, it is difficult for the heart tumor to be removed completely
• Therefore, radiation therapy and/or chemotherapy are provided
• Embolization (clotting the vessels in the tumor) may be used to provide temporary relief from the symptoms and reduce blood loss during a surgical procedure
• Heart transplantation may be undertaken in some cases; when no distant metastasis has occurred and the primary tumor, which cannot be surgically removed, is confined to the heart
• Follow-up care with regular screening and check-ups are important

How can Synovial Sarcoma of Heart be Prevented?

• Current medical research has not established a way of preventing the formation of Synovial Sarcoma of Heart
• Due to its metastasizing potential and recurrence rate, regular medical screening at periodic intervals with blood tests, scans, and physical examinations, are mandatory for those who have already been treated for this tumor

What is the Prognosis of Synovial Sarcoma of Heart? (Outcomes/Resolutions)

• The prognosis of Synovial Sarcoma of Heart is generally poor; most cases with local invasion or metastasis are fatal despite surgery to remove the tumors
• Nevertheless, the prognosis depends on a combination of factors, such as:
  • Age of the individual
  • Grade of the tumor:
  • Tumor size and location
  • Its Ki-67 value - a protein found in cells that is a good indicator of how fast the tumor cells are growing. The Ki-67 value is determined by a pathologist and is usually mentioned in the pathology report
  • Response to treatment and medical therapy

Additional and Relevant Useful Information for Synovial Sarcoma of Heart:

Primary tumors of heart are rare and they account for only 5% of heart tumors. Metastatic tumors to the heart are far more common.