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

• Telangiectatic Osteogenic Sarcoma (TOS)
• TOS (Telangiectatic Osteogenic Sarcoma)

What is Telangiectatic Osteosarcoma? (Definition/Background Information)

• Osteosarcoma forms a class of highly-cancerous, high-mortality, bone tumor. After multiple myeloma, it is the second-most common primary tumor of the bones
• Telangiectatic Osteosarcoma (TOS) is a rare, medullary type of malignant osteosarcoma. They involve the metaphyseal region of the long bones; most of them occurring in the femur or tibia, around the knees
• Telangiectatic Osteosarcoma has large blood spaces and are often mistaken for an aneurysmal bone cyst (a tumor-like bone lesion found in children)
• The exact cause of the condition is unknown and presently, it is not possible to prevent Telangiectatic Osteosarcoma occurrence
• A treatment of this bone tumor may involve surgery, chemotherapy, and radiation therapy. The prognosis of TOS depends on the stage of cancer; higher grade osteosarcomas indicate a poorer prognosis

Osteosarcomas are classified in several different ways. They may be classified based on their cause/origin, location, or even based on certain diagnostic findings.

Based on where they occur, Osteosarcoma is classified as Medullary Osteosarcoma (occurring in the bone cavity) and Surface Osteosarcoma (occurring on the bone surface).

• Medullary Osteosarcomas are of several different types, and these include:
  • Conventional Osteosarcoma
  • Osteosarcoma of Jaw Bones
  • Post-Radiation Sarcoma
  • Osteosarcoma of Paget’s Disease
  • Osteosarcoma in other Benign Conditions
  • Telangiectatic Osteosarcoma
  • Small Cell Osteosarcoma
  • Low-Grade Osteosarcoma
  • Multicentric Osteosarcoma
• Surface Osteosarcomas are of several different types, and these include:
  • Parosteal Osteosarcoma
  • Periosteal Osteosarcoma
  • High-Grade Surface Osteosarcoma

Who gets Telangiectatic Osteosarcoma? (Age and Sex Distribution)

• Telangiectatic Osteosarcoma has a bimodal (with two modes) age distribution, having the first peak during adolescence and the second peak in older adulthood
• The first peak is in the 2nd decade of life (between 10-19 years) and the condition affects children and young adults. The second peak occurs around the age of 60 years
• Some studies show a male predominance and also that males with these bone tumors have a much worse prognosis than women; though, this is not well-established
• There is no known ethnic/racial preference; the condition is known to occur worldwide

What are the Risk Factors for Telangiectatic Osteosarcoma? (Predisposing Factors)

The exact risk factors of Telangiectatic Osteosarcomas are presently unknown. However, the risk for osteosarcoma is linked to the following factors:

• Some genetic mutations are associated with osteosarcoma; including mutations in Rb gene and P53
• Individuals with bilateral retinoblastoma have a higher risk of developing the condition
• A few genetic disorders, such as Rothmund-Thompson syndrome, Bloom’s syndrome, Li-Fraumeni syndrome, hereditary multiple exostosis, and Werner syndrome, have been linked to the condition
• Paget’s disease of the bone, fibrous dysplasia, osteoblastoma, Ollier disease, and chemotherapy, are other conditions and disorders that are thought to be associated with osteosarcomas
• A previously performed radiotherapy for other cancer conditions - the tumor may be radiation-induced. The radiation has an expected side effect of damaging the genetic material in the normal cells. This can lead to the development of a “secondary” cancer
• Any physical injury or trauma

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 Telangiectatic Osteosarcoma? (Etiology)

• The exact cause and mechanism of Telangiectatic Osteosarcoma formation is unknown
• The tumor can occur de novo or spontaneously (termed as a primary osteosarcoma), or due to some preexisting conditions and abnormalities (termed as a secondary osteosarcoma)
• Such preexisting conditions could include radiation-exposure, genetic anomalies, the presence of multiple chondroma, and any well-established physical injury or trauma
• A radiation-influenced tumor takes many years to develop, after the radiation exposure has ceased. This radiation may have been previously administered for treating other cancers

What are the Signs and Symptoms of Telangiectatic Osteosarcoma?

The presentations are based on the location of the tumor. Telangiectatic Osteosarcoma signs and symptoms may include:

• Individuals have short duration of symptoms; these may include pain, swelling, and tenderness
• The tumors involve the metaphyseal region (wide portion) of the femur or tibia, around the knee. Other long bones that may be affected include the upper arm bone, fibula (calf bone)
• Patients with Telangiectatic Osteosarcoma typically present with bone fractures at the site of the tumors

How is Telangiectatic Osteosarcoma Diagnosed?

A diagnosis of Telangiectatic Osteosarcoma is made using the following tools:

• Physical examination, evaluation of patient’s medical history
• Histopathological studies conducted on a biopsy specimen - the specimen is examined under a microscope by a pathologist, to arrive at a definitive diagnosis
• X-ray studies of the tumor
• MRI scan or CT scan of the affected area

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 Telangiectatic Osteosarcoma?

Complications of Telangiectatic Osteosarcoma are dependent on the site and severity of the tumor. These include:

• Damage of the following organs due to metastasis - liver, bones, and lungs
• Usually by the time osteosarcomas are detected, chances are that they would have proliferated and metastasized aggressively, damaging organs and tissues beyond repair
• They are known to have a high recurrence rate even on surgical excision and removal
• Deep-seated tumors (those buried inside the body tissues) may cause damage to adjoining tissues and organs
• Blood loss during invasive treatment methods may be heavy
• Surgery may involve the amputation of limbs
• Damage to vital nerves, blood vessels, and surrounding structures, during surgery
• Side effects from chemotherapy (such as toxicity) and radiation therapy

How is Telangiectatic Osteosarcoma Treated?

Treatment measures for Telangiectatic Osteosarcoma may include the following:

• Surgery is the main treatment considered followed by chemotherapy. These bone tumors are known to respond very well to chemotherapy
• 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

How can Telangiectatic Osteosarcoma be Prevented?

• Current medical research have not established a method of preventing Telangiectatic Osteosarcoma occurrence
• However, the presence of any tumor or lesion should be immediately informed to the physician and periodic follow-up and screening maintained
• Regular medical screening at periodic intervals with blood tests, scans, and physical examinations are mandatory for those who have already endured the tumor. This is due to both its high metastasizing potential and chances of recurrence. Often several years of active vigilance is necessary

What is the Prognosis of Telangiectatic Osteosarcoma? (Outcomes/Resolutions)

• The overall prognosis of Telangiectatic Osteosarcoma, a rare bone tumor, is not well understood

However, several prognostic markers are identified by research which helps determine the prognosis of Telangiectatic Osteosarcoma. Many of these prognostic markers are based upon defective genes or defective proteins found in the tumor. Some of these genetic defects that alter the prognosis are explained below.

The following conditions result in or indicate a poor prognosis:

• 13q14 loss of heterozygosity (gene loss) and mutations in Rb gene
• Presence of MDR-1 gene mutation, which is a multi-drug resistant gene, results in tumor not responding to certain chemotherapy agents
• The presence of c-FAS mutations in patients result in poorer prognosis, due to a poor response of the condition to chemotherapy and a higher chances of recurrent and metastatic osteosarcoma
• HER-2 over expression in tumor
• Loss of M-TAP gene

Other factors that are related to osteosarcoma prognosis include:

• Loss of heterozygosity of 18q in patients with Paget’s disease of the bone, has been shown to increase the development of osteosarcoma, in such patients
• Studies have shown that such tumors in children have the worst prognosis, compared to young adults with the tumor
• Some studies seem to indicate that men with these bone tumors have poorer prognosis, than women; but, this has not been substantiated
• Location of the tumor also determines its outcome; tumor in distal parts of the knee and elbow, have better outcomes, than those at other locations
• The size of the tumor also determines its prognosis; normally, larger tumors have much poorer prognosis than smaller-sized tumors
• Duration of symptoms are important factors too:
  • A shorter duration of symptoms lead to a worse prognosis
  • A longer duration of symptoms lead to a better prognosis
• A presence of spontaneous necrosis leads to the worst prognosis. Spontaneous necrosis means a type of necrosis that is present due to tumor growth and not due to treatment with chemotherapy
• In general, patients with primary osteosarcoma have better prognosis than those with secondary osteosarcoma

Additional and Relevant Useful Information for Telangiectatic Osteosarcoma:

There are approximately 1000 cases of osteosarcomas diagnosed each year in the United States.