title: Fibrous dysplasia - differential diagnosis of cystic lesions in the proximal femur:a case report.
abstract: BACKGROUND
  We are reporting about the case of a 22-year old woman, who made a first visit as an outpatient with pain that arose in acute form in the area of the left groin. The patient history did not indicate a preceding trauma, or an inflammatory or malignant disease.
  
  
  METHODS
  Conventional X-ray showed the image of a cystic lesion in the area of the neck of the thigh [collum femoris] with pathological fracture in the area of the calcar. The MRT produced the diagnosis of an aneurismal bone cyst, in which the presence of juvenile bone cyst or a giant cell tumor could be taken into consideration by differential diagnosis.Owing to the pathological fracture, repair by operation of the lesion was carried out by means of spongioplastic surgery and internal fixation (DHS).
  
  
  CONCLUSIONS
  Histology produced characteristic findings fitting the condition of fibrous dysplasia, which was not included among the primary causes in the considerations offered by differential diagnosis.Therefore, this case is a good example of the fact that fibrous dysplasia must be taken into account when using differential diagnosis as one of the cystic lesions.
authors.affiliation: Department of orthopaedic surgery Elisabeth-Klinik GmbH Bigge/Olsberg, Heinrich-Sommer-Str, 4, 59939 Olsberg, Germany. s.endres@elisabeth-klinik.de.
authors.forename: Stefan
authors.initials: S
authors.lastname: Endres
authors.forename: Axel
authors.initials: A
authors.lastname: Wilke