Secondary chondrosarcoma: Malignant transformation of pre-existing hereditary and non-hereditary cartilaginous lesions

Secondary chondrosarcoma is a malignant hyaline cartilage tumour originating from a cartilaginous precursor, either osteochondroma or enchondroma. We contrast two different cases of biopsy-proven secondary chondrosarcomas resulting from benign, pre-existing cartilaginous lesions – our aim is to contrast and compare these two benign conditions consisting of multiple cartilaginous lesions – one hereditary and the other non-hereditary – and emphasise their potential for malignant transformation.