Abstract
BackgroundSecondary peripheral chondrosarcomas arising in solitary osteochondromas is an unusual complication, reported in small series. In this study, we aimed to present our experience with this rare variant of chondrosarcoma and compare results with already published data in order to determine prognostic factors for overall and disease-free survival.MethodsThe case study includes retrospective data from patients diagnosed at a single institution from 1943 to 2019. Clinical data were collected reviewing all available medical records from first to last follow-up visits. To exclude the presence of the Multiple Osteochondroma Hereditary Syndrome, few patients, with a suspect of a familial form of the disease, were evaluated for the presence of germline heterozygous variants in EXT1 and EXT2 genes. Results were summarized using descriptive statistics and statistical analysis were performed to reveal associations between variables.ResultsTwo hundred and fourteen secondary peripheral chondrosarcomas that arose exclusively from solitary osteochondromas diagnosed in a multidisciplinary setting at the IRCCS Istituto Ortopedico Rizzoli were retrospectively identified, 66.4% males and 33.6% females with a median age at diagnosis of 38 years. The local recurrence rate was 17.3%, while the metastases one was 5.1%. Besides age, a high histologic grade is the only factor associated with worse 5-year and 10-year overall survival (log-rank p = 0.0005, HR = 3.74; 95% CI 1.69–8.26). Moreover, high histological grade (HR = 3.75; 95% CI = 1.69–8.34; p = 0.001) and surgical debulking (HR = 3.71; 95% CI = 1.57–8.79; p = 0.003) were associated with a significantly worse disease-free survival.ConclusionsOur study confirm the low-grade behavior of secondary peripheral chondrosarcomas and demonstrate that the best choice of treatment for those arising in solitary osteochondromas is the wide surgical excision, when possible. Location per se is not a factor that affects prognosis, while the accurate histological grade assessment is correlated with the tumor aggressiveness and a long term follow up is necessary for this rare variant of chondrosarcoma.
Highlights
Secondary peripheral chondrosarcomas arising in solitary osteochondromas is an unusual complication, reported in small series
We aimed to present our experience with 214 secondary peripheral chondrosarcomas that arose exclusively from solitary osteochondromas (SOC) and compare it with already published data, in order to determine prognostic factors for overall and disease-free survival (DFS)
EXT1 and EXT2 mutational analyses performed in 3 patients with a positive family history for solitary osteochondroma did not detect any pathogenic variant, so excluding hereditary Multiple Osteochondromas (MO)
Summary
Secondary peripheral chondrosarcomas arising in solitary osteochondromas is an unusual complication, reported in small series. Secondary peripheral chondrosarcomas (SPCs) are malignant cartilaginous neoplasms that arise from the chondroid cap of pre-existent osteochondromas. Its incidence is not well established, ranging from about 1–7.6% in the published series [1–6], most authors agree that patients with SOC have 1–2% risk of developing a secondary chondrosarcoma. The most frequent sites of involvement of peripheral chondrosarcomas secondary to solitary osteochondromas are the ilium (20.5%), proximal and distal metaphysis of femur (19.6%), pubic bone (15.3%), proximal humerus (12%), proximal metaphysis of tibia and the scapula (6.8%, each) [4–6]
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