title: Synovial chondrosarcoma.
abstract: BACKGROUND
  Synovial chondrosarcoma (SCH) is a very rare tumor arising in the intra-articular cavity. In the majority of literature reports it is described as a malignant transformation of a pre-existing synovial chondromatosis (SC). We reported a systematic review of primary and secondary SCH described in the literature with the aim to recollect data from different case-reports and case-series, trying to summarize general aspects of this very rare disease.
  
  
  METHODS
  We collected 42 abstracts in the form of case series and case reports, which reported 67 cases of SCH. Studies were taken into account only if they proved a histological diagnosis of SCH, either primary or secondary, with or without evidence of pre-existing SC.
  
  
  RESULTS
  The average age of SCH was 56.9 years, with prevalence for male sex. The average time of malignant transformation was 11.2 years. The most affected joint was the knee (47.7%), followed by hip (34.3%) and ankle (5.9%). SCH was described as de novo sarcoma only in 13 cases (19%). Surgery ended up with amputation in 59.7% of cases. Local recurrence rate was 28.3%.
  
  
  CONCLUSIONS
  We concluded that prognosis of SCH is worse than conventional one and we speculated this is due to the difficult site of the tumor (intraarticular), diagnostic delay and inappropriate previous treatments. We consider that a rapid deterioration of a SC or rapid recurrence after synoviectomy should be considered suspicious of malignant transformation and should be treated in a reference center.
authors: Orthopaedic Department, ASST Gaetano Pini-CTO, via Bignami 1, Milano, Italy.
authors: Alessio
authors: A
authors: Biazzo
authors: Orthopaedic Department, ASST Gaetano Pini-CTO, via Bignami 1, Milano, Italy.
authors: Norberto
authors: N
authors: Confalonieri
keywords: Synovial chondrosarcoma (SCH); malignant transformation; synovial chondromatosis (SC); synovial tumor