title: Nodular osteochondrogenic activity in soft tissue surrounding osteoma in neurogenic para osteo-arthropathy: morphological and immunohistochemical study.
abstract: BACKGROUND
  Neurogenic Para-Osteo-Arthropathy (NPOA) occurs as a consequence of central nervous system injuries or some systemic conditions. They are characterized by bone formation around the main joints.
  
  
  METHODS
  In order to define some biological features of NPOAs, histological and immunohistological studies of the soft tissue surrounding osteoma and Ultrasound examination (US) of NPOA before the appearance of abnormal ossification on plain radiographs were performed.
  
  
  RESULTS
  We have observed a great number of ossifying areas scattered in soft tissues. US examination have also shown scattered ossifying areas at the early stage of ossification. A high osteogenic activity was detected in these tissues and all the stages of the endochondral process were observed. Mesenchymal cells undergo chondrocytic differentiation to further terminal maturation with hypertrophy, which sustains mineralization followed by endochondral ossification process.
  
  
  CONCLUSIONS
  We suggest that periosteoma soft tissue reflect early stage of osteoma formation and could be a model to study the mechanism of osteoma formation and we propose a mechanism of the NPOA formation in which sympathetic dystony and altered mechanical loading induce changes which could be responsible for the cascade of cellular events leading to cartilage and bone formation.
authors.affiliation: SYMPATHOS Laboratory, 67 boulevard du Général Martial Valin, 75015, Paris, France. tayebeh.youssefian@wanadoo.fr
authors.forename: T
authors.initials: T
authors.lastname: Youssefian
authors.forename: R
authors.initials: R
authors.lastname: Sapena
authors.forename: R
authors.initials: R
authors.lastname: Carlier
authors.forename: C
authors.initials: C
authors.lastname: Bos
authors.forename: A
authors.initials: A
authors.lastname: Denormandie
authors.forename: P
authors.initials: P
authors.lastname: Denys
authors.forename: A
authors.initials: A
authors.lastname: Cormier
authors.forename: M
authors.initials: M
authors.lastname: Bandelier
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D001177:Arthropathy, Neurogenic / Q000150:complications / Q000175:diagnosis / Q000473:pathology* / Q000503:physiopathology; D001859:Bone Neoplasms / Q000175:diagnosis / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology; D002454:Cell Differentiation; D019902:Chondrocytes / Q000201:enzymology / Q000473:pathology; D020219:Chondrogenesis; D003094:Collagen / Q000032:analysis; D004550:Elbow / Q000000981:diagnostic imaging; D006615:Hip / Q000000981:diagnostic imaging; D006801:Humans; D007150:Immunohistochemistry; D007717:Knee / Q000000981:diagnostic imaging; D008648:Mesoderm / Q000378:metabolism / Q000473:pathology; D009999:Ossification, Heterotopic / Q000150:complications / Q000175:diagnosis / Q000473:pathology* / Q000503:physiopathology; D010012:Osteogenesis; D010016:Osteoma / Q000175:diagnosis / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology; D010521:Periosteum / Q000473:pathology; D013314:Stress, Mechanical; D020196:Trauma, Nervous System / Q000150:complications; D014463:Ultrasonography; D016474:Weight-Bearing
chemical_list: D003094:Collagen; D000469:Alkaline Phosphatase