by Nicole Evans M.D.

Created on: June 04, 2010

There are several types of bone tumors that are benign, meaning they will never turn into malignant bone cancer.  However, the fact that the tumors are benign does not mean that they will not cause significant symptoms in individuals who develop them.  The pattern of tumor growth, potential symptoms, and required treatment varies with the type of benign bone tumor.  These include osteochondromas, osteoid osteomas, non-ossifying fibromas, intramedullary enchondromas and giant cell tumors.

Osteochondroma:

Osteochondroma is the most common benign bone tumor.  This bone tumor is characterized by exostosis (bone formation in the soft tissues) and has a characteristic stalk and cartilage cap.  Osteochondromas a more common in young children and the tumors stop enlarging at puberty. 

Benign osteochondroma tumors are usually diagnosed by x-ray and require no treatment for most teens.  On some occasions surgical excision is necessary.  Transformation of osteochondromas into malignant bone cancer is uncommon before 30 years of age and then occurs in less than 1% of all people with osteochondromas.

Osteoid osteoma:

Osteoid osteomas are benign bone tumors.  These tumors do not metastasize and have a visible nidus, a neurovascular bundle, on x-ray imaging.  Osteoid osteomas are characterized by pain at night that is relieved by over-the-counter pain killers such as aspirin.

Non-ossifying fibroma:

Non-ossifying fibromas are very common benign bone lesions.  They are usually discovered incidentally rather than by bothersome symptoms.  On x-ray, nonossifying fibromas look like “grape lesions” in the metaphysical regions of the femur (thigh bone) or tibia (inner lower leg bone).  On microscopy there are whorled fibrous cells and foam cells present.  These fibromas usually regress with the onset of puberty so are treated only with observation unless the lesion is very large and creates the possibility of fracture.

Intramedullary enchondroma:

Intramedullary enchondromas are uncommon benign bone tumors.  These tumors most often occur in the bones of the hands and/or the feet.

Giant cell tumor:

Giant cell tumors are benign and are quite uncommon.  These bone tumors occur in young adults after epiphyseal closure of the bones.  Giant cell tumors are lytic lesions (create cystic areas) and are locally aggressive eating into the epiphysis and metaphysis of bones.  These benign tumors most often occur above and below the knee and in the distal radius (forearm bone). 

On x-ray giant cell tumors look like soap bubbles in the bone.  This cancer is quite characteristic on histology which reveals the presence of many multinucleated giant cells under the microscope.  The treatment for giant cell tumors is intralesional curettage (scraping clean) and then filling the lesion with bone cement.

There are multiple varieties of benign bone tumors.  Fortunately, most of these tumors will regress without any treatment.  However, in some individuals the tumors will cause bothersome symptoms or risk of bone fracture.  Children and adults with benign bone tumors should maintain an active relationship with their physician.

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