Surface bone sarcomas: an update on current clinicopathological diagnosis and treatment.

Surface bone sarcomas are rare malignant bone tumours. Osseous and cartilaginous surface bone sarcomas are the most common, with parosteal and periosteal osteosarcomas, periosteal chondrosarcomas and secondary peripheral chondrosarcomas being the most frequent.Their clinical symptoms are non-specific and include pain for several months, swelling and limited range of motion of the adjacent joints.Prompt diagnosis is important, as biological behaviour, imaging and histopathologic characteristics, treatment and prognosis differ considerably from their conventional intramedullary counterparts. Moreover, their imaging characteristics are not infrequently non-characteristic and may be misinterpreted as juxtacortical benign lesions leading to incorrect diagnosis and treatment, with life-threatening repercussions. Molecular studies and histopathological sampling are essential for accurate diagnosis.There are still numerous issues regarding the biology, pathophysiology and treatment options of these entities due to their rarity. Cite this article: EFORT Open Rev 2021;6:905-917. DOI: 10.1302/2058-5241.6.210064.