Benign bone tumors


While malignant bone tumours are very rare, benign bone tumours are actually quite common. In one estimate nearly 40% of people walk around with some kind of bone tumor - and they are very common in children. Obviously the vast majority of these must be benign with no treatment being necessary.

Common Causes by age

Age

Benign tumors

Malignant tumors

Tumor-like conditions

Birth to 5 years

Eosinophillic granuloma

Leukaemia

Osteomyelitis

 

 

Metastatic neuroblastoma

Non-accidental injury

5 to 15 years

Unicameral bone cyst

Ewing's sarcoma

Fibrous dysplasia

 

Osteochondroma

Osteosarcoma

Osteomyelitis

 

Aneurysmal bone cyst

 

Osteofibrous dysplasia

 

Osteoid osteoma

 

Stress fracture

 

Enchondroma

 

 

 

Non-ossifying fibroma

 

 

 

Chondromyxoid fibroma

 

 

 

Chondroblastoma

 

 

15 to 20 years

Unicameral bone cyst

Osteosarcoma

Fibrous dysplasia

 

Osteochondroma

Ewing's sarcoma

Stress fracture

 

Osteoid osteoma

 

 

 

Aneurysmal bone cyst

 

 

 

Nonossifying fibroma

 

 

 

Giant cell tumor

 

 

 

Enchondroma

 

 

 

Chondroblastoma

 

 

 

Chondromyxoid fibroma

 

 

20 to 50 years

Giant cell tumor

Chondrosarcoma

Fibrous dysplasia

 

Enchondroma

 

 

Above 50 years

Brown tumors

Metastasis

Degenerate cysts

 

 

Chondrosarcoma

Metabolic disease

 

 

Malignant fibrous histiocytoma

 

 

 

Parosteal osteosarcoma

 


Challenges

Some of the challenges these benign bone tumors pose include

1. Interference of growth of the bone of origin (eg. unicameral bone cysts, osteochondroma)
2. Interference of neighbouring bones (eg. osteochondroma)
3. A tendency to fracture (eg. unicameral bone cysts)
4. Pain (especially inflammatory pain unrelated to a tendency to fracture eg. osteoid osteoma or osteoblastoma)
5. A diagnostic tendency to be mistaken for malignant tumours (eg. osteoid osteomas being mistaken for Ewing's sarcoma)
6. Destruction of the bone in aggressive lesions (e.g. Giant cell tumors)
7. Malignant transformation (eg. osteochondroma, enchondroma and even giant cell tumor)


Figure. Depending on where the tumor appears on the long bone we can make the diagnosis in up to 90% of cases with a plain x-ray


It is often more difficult to offer a cogent argument for or against a treatment modality then the case with malignant disease - because it is benign there is a tendency to feel that intervention is unnecessary. While often true, some of the risks, especially of fractures and a tendency for intractable pain make observation sometimes difficult.

Finally, while these benign bone tumours are very common they usually happen in children. Some of them do not have tumours ultra-structural features and may be better referred to as 'tumor-like' lesions as they are probably developmental in origin. These tumor-like lesions include the entities fibrous dysplasia and unicameral bone-cysts and often present with the problem of fracture risk.

Enclosed here are a number of benign conditions we have managed over the years that give but a sampling of the typical approaches that become necessary in their management.