Bone & soft-tissue tumours (question 5): a free FRCS (Tr & Orth) Section 1 question

Local staging should precede biopsy. MRI of the whole bone defines the intraosseous and soft-tissue extent, the relationship to the neurovascular bundle and joint, and any skip lesions; it shows which part of the tumour is viable and most representative, and allows the track to be placed where it can be excised. After a biopsy, haematoma and oedema alter the signal and exaggerate the apparent extent. CT of the chest and whole-body imaging complete systemic staging and are needed before treatment starts, but they are not changed by a biopsy. CT of the lesion shows matrix and cortex well but stages the marrow and soft tissue poorly. Reference: Gerrand C et al., UK guidelines for the management of bone sarcomas, Clin Sarcoma Res 2016.