How to distinguish a benign from a malignant tumour in children and when should a biopsy be done and by whom.

Bone tumours are frequent in children but most of them are benign. Moreover, the incidence and type of tumours differ from those of adults. As an orthopaedic surgeon, we will likely encounter a bone lesion in a child and we must be able to distinguish if it is a benign lesion or has malignant characteristics and it is necessary to refer it to a centre specialized in tumours. We will discuss the key points we would have to ask in the medical history, look at the physical examination and the radiological characteristics that will allow us to distinguish between a benign and a malignant bone lesion in a child. When there are doubts about the malignancy of a bone lesion or if the diagnosis is not clear, a biopsy should be performed following certain rules in a specialized centre.