Sarcomas are rare malignant tumors, with an overall incidence of 6/105/year. Bone and soft tissue connective tissue tumours encompass more than 50 different rare histotypes and more than 150 different molecular subtypes. The incidence of individual rare sarcomas subtypes is often less than 0.5/105/year. Given sarcoma rarity as a group, but even more as individual entities, few prospective clinical ...