title: [Skeletal sarcoidosis].
abstract: OBJECTIVE
  Presentation of the etiology, pathology, clinical course, radiology and differential diagnostics of skeletal sarcoidosis.
  Noncaseating epithelioid cell granulomas can trigger solitary, multiple or disseminated osteolysis, reactive osteosclerosis and/or granulomatous synovitis.
  
  
  BACKGROUND
  The incidence of sarcoidosis is 10-12 per 100,000 inhabitants per year. Skeletal involvement is approximately 14 %.
  
  
  METHODS
  Skeletal involvement occurs almost exclusively in the stage of lymph node and pulmonary manifestation. Most cases of skeletal involvement are clinically asymptomatic. In the case of synovial involvement, unspecific joint complaints (arthralgia) or less commonly arthritis can occur. Typical skin alterations can be diagnostically significant.
  Punch out lesions osteolysis, coarse destruction and osteosclerosis can occur, which are best visualized with projection radiography and/or computed tomography. Pure bone marrow foci without interaction with the bone can only be detected with magnetic resonance imaging (MRI) and more recently with positron emission tomography (PET), mostly as incidental findings. There is a predeliction for the hand and trunk skeleton.
  
  
  METHODS
  Skeletal tuberculosis, metastases, multiple myeloma, Langerhans cell histiocytosis and sarcoid-like reactions in solid tumors must be differentiated. The key factors for correct diagnosis are thorax radiography, thorax CT and dermatological manifestations.
authors.affiliation: Beratungsstelle und Referenzzentrum für Osteoradiologie, Klinikum Bremen-Mitte, Oberneulander Landstr. 58, 28355, Bremen, Deutschland. freyschmidt@radiologie-freyschmidt.de.
authors.forename: J
authors.initials: J
authors.lastname: Freyschmidt
authors.affiliation: Dermatologische Gemeinschaftspraxis, Schimmelpfengstraße 4, 34613, Schwalmstadt, Deutschland.
authors.forename: P
authors.initials: P
authors.lastname: Freyschmidt
mesh_terms: D001847:Bone Diseases / Q000000981:diagnostic imaging*; D001855:Bone Marrow Diseases / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D049268:Positron-Emission Tomography / Q000379:methods; D013902:Radiography, Thoracic / Q000379:methods*; D012507:Sarcoidosis / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Arthralgias; Chest computed tomography; Magnetic resonance imaging; Skeletal involvement; Skin manifestations