Editors

MinnaLaitinen

Bone Tumours

In the initial phase, the diagnosis of a primary bone tumour is based on clinical suspicion and x-ray findings. The abnormalities may sometimes be difficult to detect from routine x-rays.
Magnetic resonance imaging is used as a second-line investigation.
If a diagnosis is not reached with radiological investigations, a core biopsy specimen is obtained under CT guidance. The procedure is performed at the unit that will carry out any subsequent treatment.
In bone tumour surgery done in limbs, the aim is limb-sparing surgery by using large tumour prostheses or banked bone for replacing the removed part. Amputations are only seldom necessary even in malignant tumours.

Osteosarcoma is the most common primary malignant bone tumour especially in children, adolescents and young adults.
- The knee area and the upper part of the upper arm are the sites of predilection.
- X-ray findings are usually typical (picture 1).
- Prognosis is improved by early diagnosis.
- The treatment is carried out at specialized centres.
Chondrosarcoma is a tumour originating from cartilaginous tissue and is encountered in patients of a more advanced age. Its emergence may also be associated with the hereditary condition known as MHO (Multiple Hereditary Osteochondromatosis) or Ollier disease.

Osteochondroma (picture 2) and enchondroma which occurs often in the bones of the hand (picture 3) are the most common benign bone tumours.
Surgical treatment of an osteochondroma is often indicated due to the mechanical inconvenience and to the fracture risk associated with a finger enchondroma.
Enchondromas in long bones like the humerus or femur need to be evaluated by a specialist group if their diameter exceeds 3 cm.
- Non-ossifying fibroma (NOF) is a typical incidental finding which does not require follow-up or procedures.
- An osteoid osteoma is treated with thermocoagulation (picture 4). In addtion to surgical treatment of an aneurysmal bone cyst, an etoxysclerol injection is used.
- A giant cell tumour is treated locally with curettage and cement filling (picture 5). If surgery is not possible, denosumab may be used.

The most common cancers metastasising to the bone are (oestrogen-receptor positive) breast cancer, lung cancer (particularly small cell lung cancer), prostatic cancer and renal cancer.
Bisphosphonates are currently used routinely to alleviate pain and reduce bone loss.
Pathologic fractures of limb bone metastases are treated surgically. The patient's life expectancy significantly affects the surgical method.
Prophylactic intramedullary nailing can be used if there is a risk of fracture. Local radiotherapy is usually given after the procedure.

There is a high risk of pathological fractures, especially in metastases in the upper part of the femur and diaphysis. First-line treatment often consists of radiotherapy.
Lytic metastases in the spine may cause spinal cord compression through a tumour or a vertebral body compression fracture. The symptoms include weakness in the lower limbs, radicular paralysis symptoms or cauda equina syndrome.
Metastases in the cervical spine are an indication for a cervical collar before treatment is started. Immediate surgery or radiotherapy is indicated if the patient develops symptoms of paralysis.

WHO Classification of Tumours Editorial Board. Soft tissue and bone tumours. WHO classification of tumours, 5th edition, 2020.
ESMO/European Sarcoma Network Working Group. Bone sarcomas: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol 2014;25 Suppl 3():iii113-23. [PubMed]