Insights into Enchondroma, Enchondromatosis and the risk of secondary Chondrosarcoma. Review of the literature with an emphasis on the clinical behaviour, radiology, malignant transformation and the follow up.

The Enchondroma is a common, benign, cartilage forming tumour. They usually occur as a single, asymptomatic lesion. Occasionally patients present with multiple enchondromas which is generally defined as enchondromatosis. This entity encompasses several different subtypes including Ollier disease and Maffucci syndrome (enchondromatosis associated with soft tissue haemangiomas) as the most commons. Some of them have a complicated clinical course when malignant transformation occurs. This malignant progression is a well known fact especially in enchondromatosis, but up to now there is still a lack of recommendations concerning the follow up. The aim of this article is to review the clinical and imaging features of patients with solitary enchondroma and enchondromatosis focusing on the development of secondary chondrosarcoma and the follow up.