Bone and Soft Tissue Tumors: Malignant Tumors
Malignant Fibrous Histiocytoma
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What is malignant fibrous histiocytoma?
What causes malignant fibrous histiocytoma?
What are the symptoms of malignant fibrous histiocytomas?
How are malignant fibrous histiocytomas diagnosed?
How is malignant fibrous histiocytoma staged?
What are the treatments for malignant fibrous histiocytoma?
What is the long-term outlook for a patient with a malignant fibrous histiocytoma?
What is the latest research on malignant fibrous histiocytoma?
What is malignant fibrous histiocytoma?
A malignant fibrous histiocytoma is a type of cancerous tumor that can originate in either bone or, most often, in the soft tissues that connect, support or surround organs and other body structures.
While it is among the most common types of soft tissue tumors found in adults, it is rarely found in children, making up only a tiny percentage of all soft tissue sarcomas, which as a group account for only 1 percent of new cancer cases in children each year.
Malignant fibrous histiocytoma is a painless mass that most often occurs in the extremities, although it can occur anywhere in the body. The condition most commonly spreads (metastasizes) to the lungs, but can also invade the lymph nodes and bone.
What causes malignant fibrous histiocytoma?
The exact cause of malignant fibrous histiocytoma is not entirely understood, however, studies have indicated that genetic alterations may play a role. Scientists are investigating the role of an associated genetic abnormality on the short arm of chromosome 19 that may give rise to this disease. It is known that malignant fibrous histiocytoma originates in primitive mesenchymal cells (undifferentiated cells that give rise to such structures as connective tissues, blood, lymphatics, bone and cartilage).
The disease has also been linked to radiation treatment for breast cancer, retinoblastoma and Hodgkin's Lymphoma. A malignant fibrous histiocytoma originating in the bone has been linked to pre-existing abnormalities such as Paget's disease or fibrous dysplasia of the bone.
What are the symptoms of malignant fibrous histiocytomas?
Because malignant fibrous histiocytomas usually affect tissue that is elastic and easily moved, a tumor may exist a long time before being discovered, growing large, and pushing around surrounding tissue. The following are the most common symptoms of malignant fibrous histiocytomas. However, each child may experience symptoms differently. The symptoms vary greatly depending on size, location and spread of the tumor.
Symptoms may include:
- painless swelling or lump
- pain or soreness caused by suppressed nerves or muscles
- limping or other difficulty using legs, arms, feet or hands
The symptoms of malignant fibrous histiocytoma may resemble other conditions or medical problems. Always consult your child's physician for a diagnosis.
How are malignant fibrous histiocytomas diagnosed?
In addition to a complete medical history and physical examination, the most conclusive diagnostic procedure for soft tissue sarcomas is a biopsy, a single tissue sample taken from the tumor through a simple surgical procedure. This form of cancer is distinguished from other sarcomas by its appearance under a microscope.
Your child will likely undergo various imaging studies that will include one or more of the following:
X-ray – a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film. X-rays are very useful in the diagnosis of soft tissue tumors and frequently allow the physician to distinguish benign from malignant bone tumors. It is the first diagnostic study, and it often gives the doctor information regarding the need for further testing.
Magnetic resonance imaging (MRI) – a diagnostic procedure that uses a combination of large magnets, radio frequencies and a computer to produce detailed images of organs and structures within the body. This test outlines the extent of the tumor and the relationship of the tumor to the nerves, muscles and blood vessels.
Computerized tomography scan (also called CT or CAT scan) – a diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce cross-sectional images (often called slices) both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat and organs. CT scans are more detailed than general X-rays
Bone scan – a nuclear imaging method to detect bone and metastatic tumors . It will determine if there are abnormalities in other bones. This tests does not distinguish between tumor, infection or fractures.
Additional tests may include:
- Complete blood count (CBC) –- a measurement of size, number and maturity of different blood cells in a specific volume of blood.
- Blood tests (including blood chemistries)
How is malignant fibrous histiocytoma staged?
Once malignant fibrous histiocytoma has been diagnosed, the tumor is staged. This process indicates how far the tumor has spread from its original location. The stage of a tumor and how aggressive it is suggests which form of treatment is most appropriate, and gives some indication of prognosis.
A malignant fibrous histiocytoma may be localized, meaning it has not spread beyond the bone where it arose or beyond nearby tissues, or metastatic, meaning it has spread to lungs, bones other than the bone that the tumor originated in, or to other organs or structures of the body.
What are the treatments for malignant fibrous histiocytoma?
Specific treatment for malignant fibrous histiocytoma will be determined by your child's physician based on:
- your child's age, overall health, and medical history
- extent and location of the disease
- your child's tolerance for specific medications, procedures, or therapies
- how your child's doctor expects the disease may progress
- your opinion or preference
Treatment may include:
Surgery
Surgery for malignant fibrous histiocytomas involves the biopsy, surgical removal of the tumor, bone/skin grafts, and/or reconstruction, all performed by a surgeon. The type of surgery will depend on the size and location of the tumor, and whether the cancer has spread. If the tumor occurs in a limb, either of the following may be an option:
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Limb-salvage surgery: It is sometimes necessary to remove all or part of a limb. In most cases, however, limb-sparing surgery is used to avoid amputation. This however is considered only if the orthopedic surgeon determines that it is possible that the tumor, and wide margins of healthy tissue surrounding the tumor, can be removed.
Through limb-sparing surgery, all of the tissues involved with the tumor, including some degree of muscle surrounding it, is removed, while nearby tendons, nerves and vessels are saved. The bone that is removed is replaced with a bone graft or with a metal rod. Subsequent surgery may be needed to repair or replace rods, which can become loose or break.
Patients who have undergone limb-salvage surgery need intensive rehabilitation. It may take as long as a year for a patient to regain full use of a leg following limb-salvage surgery. Some patients who have limb sparing resections may eventually have to undergo amputation. Radiation therapy and/or chemotherapy are sometimes given either before surgery to shrink the tumor, or after surgery to kill remaining cancer cells.
Amputation: In certain cases, if your child's orthopedic surgeon determines that the tumor cannot be removed because, for example, it involves the nerves and blood vessels, amputation is the only option.
During the operation, doctors ensure that muscles and skin form a cuff around the amputated bone. A cast is applied in the operating room which permits a temporary artificial leg (prosthesis) to be applied during the first few post-operative days for walking. Crutches are used for several weeks. As the swelling decreases (10 to 14 days) the patient is fitted for a plastic, temporary socket and prosthesis, which is used for three to four months until the stump is healed sufficiently to accept a permanent artificial leg.
The advantages of an amputation are that it is a simple operation with minimal chances of surgical complication and it definitively removes the local tumor. The functional outcome is good with the modern prostheses available today and with "immediate-fit" prostheses applied in the operating room. Although the patient will probably have a limp with above-the-knee amputations, the procedure is functional and stable. He/she will be able to walk, climb stairs, swim (with the prosthesis on or off) and participate in many sports such as skiing, basketball, baseball, and tennis although running will be limited. The functional limitations are left to the imagination and determination of the patient.
Radiation Therapy
Radiation uses high energy rays from a specialized machine to damage or kill cancer cells and shrink tumors. This is sometimes used in conjunction with surgery for malignant fibrous histiocytoma, either before or after resection of the tumor. On rare occasions radiation alone is used for treatment of the primary tumor.
Chemotherapy
Chemotherapy is a drug treatment that works by interfering with the cancer cell's ability to grow or reproduce. Different groups of drugs work in different ways to fight cancer cells and shrink tumors. Chemotherapy may be used alone for some types of cancer or in conjunction with other therapy such as radiation or surgery. Often, a combination of chemotherapy drugs is used to fight a specific cancer. Certain chemotherapy drugs may be given in a specific order depending on the type of cancer it is being used to treat. While chemotherapy can be quite effective in treating certain cancers, the agents do not differentiate normal healthy cells from cancer cells. Because of this, there can be many adverse side effects during treatment. Being able to anticipate these side effects can help the care team, parents, and child prepare and, in some cases, prevent these symptoms from occurring, if possible. Chemotherapy is a systemic treatment, meaning it is introduced into the bloodstream and travels throughout the body to kill cancer cells. Chemotherapy may be given:
- as a pill to swallow
- as an injection into the muscle or fat tissue
- intravenously (directly to the bloodstream; also called IV)
- intrathecally (given directly into the spinal column with a needle)
Supportive Care
Supportive care refers to any type of treatment to prevent and treat infections, side effects of treatments and complications and to keep your child comfortable during treatment.
Continuous Follow-Up Care
A schedule of follow-up care will be determined by your child's physician and other members of their care team to monitor ongoing response to treatment and possible late effects of treatment.
Treatment options will vary greatly, depending on your child's individual situation. Your child's physician and other members of your care team will discuss these with you in depth.
What is the long-term outlook for a patient with a malignant fibrous histiocytoma?
Prognosis greatly depends on:
- the extent of the disease
- the size and location of the tumor
- a presence or absence of metastasis
- the tumor's response to therapy
- the age and overall health of your child
- your child's tolerance of specific medications, procedures or therapies.
- new developments in treatment
As with any cancer, prognosis and long-term survival can vary greatly from individual to individual. Prompt medical attention and aggressive therapy are important for the best prognosis. Continuous follow-up care is essential for a child diagnosed with a malignant fibrous histiocytoma. Side effects of radiation and chemotherapy, as well as recurrence of the disease, can occur in survivors.
What is the latest research on malignant fibrous histiocytoma?
Children's Hospital and Dana-Farber Cancer Institute are conducting numerous research studies that will help clinicians better understand and treat malignant fibrous histiocytomas and other soft tissue and bone sarcomas.
Other types of treatment currently being studied include:
- Angiogenesis inhibitors – substances that may be able to prevent the growth of tumors by blocking the formation of new blood vessels that feed the tumors.
- Biological therapies – a wide range of substances that may be able to involve the body's own immune system to fight cancer or lessen harmful side effects of some treatments.
- Neoadjuvant chemotherapy and radiotherapy – combining radiation and chemotherapy may reduce the incidence of metastatic disease in synovial sarcoma. Treatments using chemotherapy and radiotherapy before resecting the primary tumor in synovial sarcoma in adults and children are being investigated.
