Clear cell chondrosarcoma of bone is considered a low-grade malignant tumor in the last WHO classification of soft tissue and bone tumors; however, it is reported that recurrences and metastasis can occur. Considering the uncertain prognosis of this rare tumor, with some cases that historically seems to pursue a bad prognosis, we decided to collect all the Italian cases of clear cell condrosarcoma, in order to better understand its natural history and prognosis.

Inclusion Criteria:

• Male and female patients with diagnosis of clear cell chondrosarcoma and chondrosarcoma with a clear cell component treated from 01 Jan 1982 to 31 Dec 2023
• Information available (date of primary tumor diagnosis, local treatments, systemic treatment, response to systemic treatment, date of progression) and date and status at last follow-up
• Imaging studies available for revision
• Histological slides available for revision

Exclusion Criteria:

• - Diagnosis different from clear cell chondrosarcoma or chondrosarcoma with a clear cell component;
• Absence of radiological and/or clinical data