title: Primary synovial chondromatosis: a reassessment of malignant potential in 155 cases.
abstract: OBJECTIVE
  Primary synovial chondromatosis (PSC) is a rare disorder characterised by cartilage formation in synovium-lined joints, tendon sheaths and bursae. It is thought that PSC cartilage arises from the proliferation of mesenchymal cells, which exhibit cartilaginous metaplasia in subintimal connective tissue. There are reports of transformation of PSC to chondrosarcoma, although the precise incidence and nature of this complication is uncertain. In this study we carried out a retrospective review PSC to determine the incidence of sarcomatous change in this condition, in addition to the clinical, radiological and pathological features that characterise this complication
  
  
  METHODS
  We reviewed 155 cases of PSC and identified 4 cases (3 in the hip joint; 1 in the elbow joint) of aggressive behaviour and chondrosarcoma-like histology.
  
  
  RESULTS
  Radiologically, these cases were all reported as showing features consistent with PSC and aggressive extra-articular soft tissue/bone involvement. Histologically, in addition to typical features of PSC, there was morphological evidence of peri-articular soft tissue and, in 2 cases, bone involvement by an infiltrating cartilaginous tumour. These tumours all behaved as locally aggressive neoplasms and did not give rise to metastasis.
  
  
  CONCLUSIONS
  Our findings show that chondrosarcoma arises infrequently in PSC (approximately 2.5 %), and that this complication occurs most commonly in the hip joint (approximately 11 % of cases of hip PSC). These tumours behaved mainly as low-grade, locally aggressive tumours analogous to atypical cartilaginous tumour of bone/grade 1 chondrosarcoma of bone.
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal and Sciences, University of Oxford, Nuffield Orthopaedic Centre, Oxford, OX3 7HE, UK.
authors.forename: C
authors.initials: C
authors.lastname: McCarthy
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal and Sciences, University of Oxford, Nuffield Orthopaedic Centre, Oxford, OX3 7HE, UK.
authors.forename: W J
authors.initials: WJ
authors.lastname: Anderson
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal and Sciences, University of Oxford, Nuffield Orthopaedic Centre, Oxford, OX3 7HE, UK.
authors.forename: M
authors.initials: M
authors.lastname: Vlychou
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal and Sciences, University of Oxford, Nuffield Orthopaedic Centre, Oxford, OX3 7HE, UK.
authors.forename: Y
authors.initials: Y
authors.lastname: Inagaki
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal and Sciences, University of Oxford, Nuffield Orthopaedic Centre, Oxford, OX3 7HE, UK.
authors.forename: D
authors.initials: D
authors.lastname: Whitwell
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal and Sciences, University of Oxford, Nuffield Orthopaedic Centre, Oxford, OX3 7HE, UK.
authors.forename: C L M H
authors.initials: CL
authors.lastname: Gibbons
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal and Sciences, University of Oxford, Nuffield Orthopaedic Centre, Oxford, OX3 7HE, UK. nick.athanasou@ndorms.ox.ac.uk.
authors.forename: N A
authors.initials: NA
authors.lastname: Athanasou
mesh_terms: D000293:Adolescent; D000328:Adult; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D015838:Chondromatosis, Synovial / Q000000981:diagnostic imaging / Q000473:pathology*; D002813:Chondrosarcoma / Q000000981:diagnostic imaging / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011230:Precancerous Conditions / Q000000981:diagnostic imaging / Q000473:pathology*; D055815:Young Adult
keywords: Chondrosarcoma; Hip; Synovial chondromatosis; Tumour