When cells divide uncontrollably and abnormally, it can form a lump or mass of tissue. The mass or lump of tissue formed is called a tumour. Bone tumours form in the bones. As the tumour grows, the abnormal tissues can end up displacing the healthy tissues.
Fortunately, not all bone tumours are cancerous and many bone tumours are benign. However, while benign tumours are not fatal and are unlikely to spread to other parts of the body, they can still be dangerous and require medical attention. While not fatal, they can grow and end up compressing healthy bone tissues. Sometimes, they can also weaken the bone and lead to fractures.
On the other hand, other tumours can be cancerous or malignant. Bone tumours that are malignant can cause cancer to spread to other parts of the body.
Different Types of Benign Bone Tumours
Osteochondromas – Benign tumours are more prevalent than malignant ones. Osteochondroma is considered the most common among the benign tumours, according to the American Academy of Orthopaedic Surgeons (AAOS). Osteochondromas account for at least 40 per cent of all benign bone tumours. The condition is common among teenagers and adolescents. Osteochondromas often develop near actively growing ends of long bones (i.e. leg or arm bones). Specifically, osteochondromas often develop in the femur (the thighbone’s lower end), tibia (lower leg bone’s upper end), and the humerus (upper arm bone’s upper end).
Enchondroma – The cartilage cyst that grows inside the bone marrow is called an enchondroma. The condition can develop during childhood and persist until adulthood. Enchondromas tend to also become part of syndromes known as Maffucci’s and Ollier’s syndrome. This type of bone tumour often develops in the feet and hands and the long bones of both the thigh and the arm. Of interest is the fact that enchondromas of the hands and feet never become malignant unlike those in larger bones.
Aneurysmal Bone Cyst – This condition starts in the bone marrow and is considered an abnormality of the blood vessels. Since it affects the growth plates and can grow rapidly, it can be particularly destructive.
Giant Cell Tumour – While considered rare, this type of bone tumour can grow aggressively. Often affecting adults, giant cell tumour often develops in the bone’s rounded end but away from the growth plate.
Nonossifying Unicameral Fibroma – Nonossifying fibroma often develops in the leg and is a simple and solitary bone cyst. The condition often affects adolescents and children.
Fibrous Dysplasia – Fibrous dysplasia is considered a gene mutation. The condition can make the bones fibrous (softer). They are more prone to stress fractures and develop into curved bent bones over a period of time with repeated fractures and healing.
Malignant Bone Tumours
Osteosarcoma – Osteosarcoma is considered the second most common type of bone cancer. This type of bone cancer typically develops in the knee, shoulder, and around the hip. Osteosarcomas can grow rapidly and spread to other parts of the body. This condition is also called osteogenic sarcoma.
Chondrosarcoma – This type of bone cancer often develops in the shoulders, pelvis, and thigh bones. Chondrosarcoma often affects middle-aged individuals and older adults.
Ewing Sarcoma Family of Tumours (ESFTs) – ESFTs often strikes young adults and adolescents. However, it can also affect children as young as 5 years of age. This kind of bone tumour often develops in the pelvis, ribs, upper arms, thigh, backbone, and the skull. It often begins in the medullary cavities (the bone cavities where the bone marrow is produced). Apart from the bone, ESFTs can also develop in soft tissues like the muscle, fat, and blood vessels. The condition is more common among girls and has the tendency to spread quickly. Mortality rates are high.
Secondary Bone Cancer
When the cancer starts somewhere else in the body but spread to the bones, it is referred to as “secondary bone cancer.” The condition often affects older adults. Cancer types that are most likely to spread to the bones include:
- Thyroid Gland
The exact causes of bone tumours are not known. However, radiation treatment, exposure to chemical agents, genetics, and chronic bone infection have been identified as some of the possible causes. For instance, osteosarcoma has been associated with high radiation doses (and other anticancer drugs), especially in children. However, a direct cause has yet to be identified.
One of the most common symptoms of bone cancer is a dull ache in the affected bone. The pain can start off as occasional but will eventually become constant and severe. The pain can become so severe that it keeps patients awake at night.
In other cases, patients with undiscovered bone tumours can suffer bone fractures even from the most minor and insignificant injuries. This can be because the affected bone is already weakened and therefore more prone to injury. This condition is also known as a pathological fracture.
Other times, swelling can also manifest at the tumour site. Patients can also experience fevers or night sweats. Loss of appetite and loss of weight are serious signs of tumour spread in the body. While some will not experience pain in other cases, it is possible that they will notice tissue masses in some parts of their body. Those with benign bone tumours might not experience or notice any symptoms and the tumour might not be detected until an imaging scan is done.