title: Intramuscular chondroid lipoma: magnetic resonance imaging diagnosis by 'fat ring sign'.
abstract: BACKGROUND
  Chondroid lipoma is an extremely rare variant of benign lipomatous lesions that is composed of lipoblasts, mature fat, and chondroid matrix. Although benign lipomatous lesions are the most common soft tissue tumors and imaging findings are often pathognomonic, there have been few reports describing the imaging features of chondroid lipoma.
  
  
  METHODS
  We present magnetic resonance imaging (MRI) findings of a pelvic intramuscular chondroid lipoma in a 59 year-old man and describe a "fat ring sign" that may be useful to diagnose this rare tumor radiologically.
  
  
  CONCLUSIONS
  Magnetic resonance imaging findings of a chondroid lipoma may be heterogenous according to the distribution of the fatty and chondroid tissue. However, in the presence of "fat ring sign," radiologists should consider a diagnosis of chondroid lipoma preoperatively.
authors.affiliation: Department of Radiology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
authors.forename: Adalet Elçin
authors.initials: AE
authors.lastname: Yıldız
authors.affiliation: Department of Radiology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
authors.forename: Üstün
authors.initials: Ü
authors.lastname: Aydıngöz
authors.affiliation: Department of Pathology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
authors.forename: Cenk
authors.initials: C
authors.lastname: Sökmensüer
authors.affiliation: Department of Radiology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
authors.forename: Muşturay
authors.initials: M
authors.lastname: Karçaaltıncaba
keywords: Chondroid lipoma; MRI; pelvis