Bone tumours include both benign and malignant lesions:

• Benign lesions may cause pain, expansion into local structures, joint dysfunction and predispose to pathological fractures.
• Secondary malignant tumours are much more common than primary malignant bone tumours.

Classification

Benign

• Bone: osteoid osteoma
• Cartilage: chondroma, osteochondroma
• Fibrous tissue: fibroma
• Bone marrow: eosinophilic granuloma (see separate article Langerhans' Cell Histiocytosis)
• Vascular: haemangioma
• Uncertain: giant cell tumour

Malignant

• Bone: osteosarcoma
• Cartilage: chondrosarcoma
• Fibrous tissue: fibrosarcoma
• Bone marrow: Ewing's sarcoma¹, myeloma
• Vascular: angiosarcoma
• Uncertain: malignant giant cell tumour

Benign bone tumours

Osteoid osteoma

• Usually less than 1 cm in diameter and surrounded by dense osteoid.
• Often occurs in young adults.
• Most common sites are the tibia, femur and vertebrae.
• Presents with pain, which is often worse at night and relieved by non-steroidal anti-inflammatory drugs.
• X-ray has characteristic appearance of a radiolucency surrounded by dense bone.
• Local excision is curative.

Osteochondroma

• One of the most common benign bone tumours.
• Sessile or pedunculated lesions arising from the cortex of a long bone adjacent to the epiphyseal plate.
• Lesions can be single or multiple.
• Often presents in adolescence as cartilaginous overgrowth at epiphyseal plate.
• Grows with the underlying bone.
• Presents as a painless lump or occasionally joint pain.
• Multiple hereditary exostosis is an autosomal dominant disorder with a mild decrease in stature, normal intelligence, and multiple osteochondromas. It is commonly accompanied by leg length discrepancy, knee and elbow angular deformities, and other skeletal abnormalities.
• Excision should be considered if it is causing significant symptoms.
• Problems include nerve compression (especially peroneal nerve), ankle diastasis, angular deformities. Malignant transformation to low-grade chondrosarcoma is more common with multiple osteochondromas and more proximal lesions.

Chondroma

• Lesions may be single or multiple (Ollier's disease).
• Appears in tubular bones of hands and feet.
• X-ray shows well-defined osteopenic area in the medulla.
• Lesion should be excised and bone grafted.

Giant-cell tumour (osteoclastoma)

• Represents about 20% of primary bone tumours.
• Aggressive, locally recurrent tumour with a low metastatic potential.
• Found in sub-articular cancellous region of long bones. Most lesions occur in closed epiphyses around the knee joint and distal radius.
• Only occurs after closure of epiphyses.
• Patients are usually aged between 20 and 40 years. It is more common in females.
• X-ray shows an asymmetric rarefied area at the end of a long bone.
• Cortex is thinned or even perforated.
• Treatment is by local excision and grafting often leads to recurrence.
• Wide excision and joint replacement is the treatment of choice.
• Amputation if there is malignant or recurrent tumour.

Chondroblastoma

• Rare, normally in epiphysis of long bones, e.g. the hip, shoulder and knee.
• Usually presents at age 10-19 years with pain in the joint, muscle atrophy and tenderness.
• Treatment is with curettage and bone grafting.

Osteoblastoma

• Locally destructive progressive lesion commonly found in vertebrae.
• Usually presents with dull aching pain.
• Frequently needs biopsy to exclude malignancy.
• Treatment is with curettage/bone grafting or en bloc excision.

Fibromas

• Occur in 40% of children >2 years.
• Usually asymptomatic.
• Usually no treatment except when occupies >50% bone diameter when there is a need for curettage/bone grafting to avoid pathological fracture.

Unicameral bone cysts

• Fluid-filled lesion. Rare before the age of 3 years and after skeletal maturity.
• Usually present as pathological fracture (asymptomatic before then) following relatively minor trauma, normally involving the proximal humerus or femur.
• Treatment is to allow the fracture to heal and then aspirate and inject with either methylprednisolone or bone marrow.

Aneurysmal cyst

• Usually present before the age of 20, with pain and swelling.
• They are cavernous spaces filled with blood and solid lumps of tissue.
• They mainly affect the femur, tibia and spine, which may lead to cord or nerve root compression resulting in neurological symptoms.
• They grow rapidly and may be confused with malignancy.
• Treated with curettage/bone grafting or excision.
• Recurs in 20-30%, usually in the first 1-2 years after treatment and mainly in younger children.

Fibrous dysplasia

• Fibrous replacement of cancellous bone, may be multiple or solitary, stable or progressive.
• Usually asymptomatic but, if involving the skull, may cause swelling or exophthalmos.
• Femoral involvement causes pain and a limp. May also cause limb length discrepancy, bowing and pathological fractures.

Osteofibrous dysplasia

• Presents in children aged 1-10 years.
• Usually involves the tibia with anterior swelling or enlargement of the leg. Usually painless.
• Treatment is with excision and bone grafting, delayed until after the age of 10 years because of the high risk of recurrence if younger.

Eosinophilic granuloma

• Most common in boys aged 5-10 years; usually occurs before the age of 30.
• Most often affects the skull with local pain and swelling, marked tenderness and warmth in the area.
• Treatment is with curettage/bone grafting, low-dose radiotherapy or steroid injection.

Malignant bone tumours

Osteosarcoma

• The most common primary bone malignancy in children.²
• It is more common in males and most often presents in the second and third decades of life.
• Usually occurs between the ages of 10 and 20 years.
• In later life is seen associated with Paget's disease of bone.
• Occurs in the metaphyses of long bones. The most common sites are around the knee or proximal humerus.
• Often presents as a relatively painless tumour.
• Destroys bone and spreads into the surrounding tissue. Rapidly metastasises to the lung.
• X-ray shows combination of bone destruction and formation. Soft tissue calcification produces a 'sunburst' appearance.
• Treatment is now initially with chemotherapy followed by limb salvage surgery and further chemotherapy. The form of chemotherapy is still not yet widely agreed but combinations of doxorubicin and cisplatin with or without methotrexate have given disease-free survival at 5 years of around 50%.^3,4
• The prognosis is worst with proximal and axial skeletal lesions. Presence of metastases is found in 10-20% of patients and carries a poor prognosis (11% 5 years' survival).³

Chondrosarcoma

• Second to osteosarcoma in prevalence of bony sarcomas.
• May arise from pre-existing lesions (osteochondromas, chondromas) or they can be primary.
• They are usually associated with dull, deep pain.
• Radiographs may show invasiveness and soft tissue extension.
• Occurs in two forms:
  • Central: tumour in the pelvis or proximal long bones.
  • Peripheral: tumour in the cartilaginous cap of an osteochondroma.
• Tend to metastasise late.
• Wide local excision is often possible.

Metastatic tumours

• The most common bone malignancies are metastatic carcinomas.
• They are usually multiple but may be solitary.
• The most common primaries are breast, prostate, lung, kidney and thyroid.
• Wilms' tumour and neuroblastoma are the most common metastatic lesions in childhood.

Epidemiology

• Primary malignant bone tumours are rare.
• Secondary tumours are more common, especially in the elderly.

Presentation

• Most present with pain, swelling and localised tenderness.
• Rapid growth and erythema are suggestive of malignancy.
• May cause pathological fractures.

Investigations

• Plain X-ray
• MRI and CT scan
• Bone scan⁵
• Biopsy
• Investigation of any occult primary lesion, especially breast, prostate, lung, kidney and thyroid

Document references

1. Ludwig JA; Ewing sarcoma: historical perspectives, current state-of-the-art, and opportunities for targeted therapy in the future. Curr Opin Oncol. 2008 Jul;20(4):412-8. [abstract]
2. Eyre R, Feltbower RG, Mubwandarikwa E, et al; Incidence and survival of childhood bone cancer in northern England and the West Midlands, 1981-2002. Br J Cancer. 2009 Jan 13;100(1):188-93. [abstract]
3. Jaffe N, Carrasco H, Raymond K, et al; Can cure in patients with osteosarcoma be achieved exclusively with chemotherapy and abrogation of surgery? Cancer. 2002 Nov 15;95(10):2202-10. [abstract]
4. Chou AJ, Geller DS, Gorlick R; Therapy for osteosarcoma: where do we go from here? Paediatr Drugs. 2008;10(5):315-27. [abstract]
5. Bone Scintigraphy - Procedure Guidelines for Tumour Imaging, European Association of Nuclear Medicine (2003)

Internet and further reading

• Bone cancer. Robert Grimer, an orthopaedic surgeon, explains the two different types of bone cancer, the questions to ask if you’re diagnosed and the treatment options. A short video from NHS Choices. (January 2008)
• Bonetumor.org
• Macmillan Cancer Suppport (Cancerbackup);Primary bone cancer information centre.
• Tan ML, Choong PF, Dass CR; Osteosarcoma: Conventional treatment vs. gene therapy. Cancer Biol Ther. 2009 Jan;8(2):106-17. Epub 2009 Feb 12. [abstract]

Acknowledgements