by Nicole Evans M.D.

Created on: June 04, 2010   Last Updated: June 05, 2010

There are several types of malignant bone tumors.  Secondary bone cancer that occurs when cancer from elsewhere in the body spreads to the bone is much more common than primary bone cancer that originates within the bone.  Multiple myeloma is the most common secondary bone cancer.  Primary bone cancers include osteosarcoma, Ewing sarcoma and chondrosarcoma.

Osteosarcoma:

Osteosarcoma is the most common form of primary bone cancer and is most common in the teenage age group.  It often occurs in the metaphyseal area of long bones such as the distal femur (thigh bone) and proximal tibia (inner lower leg bone.) 

The pain created by osteosarcomas is usually described by patient’s as a deep pain.  Often an enlarging mass is detected on palpation.  Osteosarcomas do metastasize and seed to other areas in the body.  This bone cancer most often metastasizes to the lungs via the bloodstream. 

The tumor cells of osteosarcoma can also extend into the soft tissue overlying the bone and when visualized on x-ray imaging this may appear similar to sun rays or as the characteristic “Codman’s triangle”, a radioopaque triangle arising from the bone. 

At a cellular level the tumor appears as spindle shaped cells that rapidly divide to form osteoid bone.  Osteosarcoma is an interesting bone cancer in that it is both osteoblastic and osteolytic.  Osteoblastic means that it causes bone growth and bony deformities while osteolytic means that osteosarcoma causes bone breakdown and cyst formation in bones. 

Ewing sarcoma:

Ewing sarcoma is another malignant bone cancer.  It is significantly less common than osteosarcoma and the origin of these tumor is uncertain.  Ewing sarcoma occurs most often in individuals who are 7 to 20 years of age and is more common in boys.  It is associated with a genetic translocation mutation known as t(11;22.)

The tumor often originates in the femur, humerus and ilium (a pelvic bone).  Ewing sarcomas often mimic a bone infection called osteomyelitis.  Ewing sarcoma resembles osteomyelitis in terms of symptoms as well as on x-ray imaging.

Under the microscope, it is difficult to distinguish Ewing sarcoma from another form of cancer called lymphoma.  The treatment for Ewing sarcoma involves chemotherapy and surgery or radiation therapy.  There is approximately a 60% patient survival at 5 years after the diagnosis of this malignant cancer of the bone.

Chondrosarcoma:

Chondrosarcomas are another form of uncommon malignant bone cancer.  These tumors can occur in the pelvis, spine and/or scapula (shoulder blade).  Chondrosarcomas are associated with the genetic medical disorder known as multiple endocrine disorder or MEN.

The majority of primary malignant bone tumors occur in younger age groups and are located in the leg or pelvic area.  Therefore, complaints of hip and leg pain in children should be taken seriously by parents and physicians.  Secondary bone tumors are more common in older individuals with known primary cancers such as prostate, breast, multiple myeloma and lymphoma. 

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