Malignant fibrous histiocytoma (MFH, pleomorphic undifferentiated sarcoma, undifferentiated pleomorphic sarcoma) is a type of cancer that is the most common soft tissue sarcoma of late adult life, most commonly occurring between age 50-70. In rare cases MFH does occur in children, but it is usually in a less aggressive form. However, malignant tumors have occurred in children as young as 13. It occurs more often in caucasians than those of African or Asian descent. Its male:female predominance is 2:1.
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:
- A painless swelling or lump
- Pain or soreness caused by supressed 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.
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 Disease. 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.
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-rays - 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 they 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, radiofrequencies 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 that general x-rays
Bone scans - 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.
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.
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, boneskin 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:
Limb-salvage surgery: It is sometime 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 3 to 4 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.