Non-haematogenic tumours arising primarily in the bone are rare. They are classified based on their histomorphology. Within the osteofibrous group the spectrum ranges from benign, exclusively... Show moreNon-haematogenic tumours arising primarily in the bone are rare. They are classified based on their histomorphology. Within the osteofibrous group the spectrum ranges from benign, exclusively fibrous lesions to high-grade osteosarcoma. These osteofibrous tumours show histological variability in a given entity as well as similarities between entities. The purpose of this thesis was to reveal the meaning of the phenotypic spectrum of osteofibrous tumours. In retrospect, the histological subtype of osteosarcoma is a predictive factor for response to chemotherapy, late relapse and risk of a hereditary cancer syndrome, but not for survival. However, the poor histological response of chondroblastic osteosarcomas to neo-adjuvant chemotherapy did not translate in a lower survival rate. On the other hand, overlapping histological and/or clinical parameters between certain tumour entities such as for example adamantinoma and Ewing sarcoma, and desmoplastic fibroma of bone and desmoid type fibromatosis of soft tissue, does not justify to classify these tumours as part of one disease entity as was demonstrated in this thesis. Thus, the correct classification, reclassification of known entities on new insights and sub-classification on phenotypic differences, when related with biological behaviour, has implications for clinical practice and disease management, and contributes to optimal patient care. Show less
