title: Intramuscular migration of calcium hydroxyapatite crystal deposits involving the rotator cuff tendons of the shoulder: report of 11 patients.
abstract: OBJECTIVE
  The intent of the study is to describe an unusual pattern of intramuscular migration of calcific deposits related to hydroxyapatite deposition disease (HADD) involving the rotator cuff, to illustrate the characteristic imaging features of this phenomenon, and to discuss the clinical significance of such migration.
  
  
  METHODS
  A series of cases of intramuscular accumulation of calcium hydroxyapatite crystals collected over a 7-year period at multiple hospitals within the same academic institution were retrospectively reviewed.
  
  
  RESULTS
  The patient group was composed of seven men and four women, ranging in age from 51 to 79 years, with a mean age of 63 years. All subjects presented with acute shoulder pain. The majority of subjects reported the spontaneous onset of the symptoms (64%), while others reported weight lifting (27%) and a fall on the arm (9%) as the mechanisms of injury. The right shoulder was affected in 73% of the subjects. The supraspinatus was the most commonly affected muscle (82%), followed by the infraspinatus muscle (36%).
  
  
  CONCLUSIONS
  Knowledge of the imaging features of intramuscular migration of hydroxyapatite deposits is important in order to avoid the erroneous diagnosis of other causes of muscle edema and inflammation such as myotendinous injury, myositis, subacute denervation, and neoplasm.
authors.affiliation: Department of Radiology, University of California San Diego Medical Center, 8899 University Center Lane Suite 370, San Diego, CA, 92122, USA. bruno_pgp@hotmail.com.
authors.forename: Bruno P G
authors.initials: BP
authors.lastname: Pereira
authors.affiliation: Radiology Service, VA San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA, 92161, USA. ericchangmd@gmail.com.
authors.forename: Eric Y
authors.initials: EY
authors.lastname: Chang
authors.affiliation: Department of Radiology, University of California San Diego Medical Center, 8899 University Center Lane Suite 370, San Diego, CA, 92122, USA. dresnick@ucsd.edu.
authors.forename: Donald L
authors.initials: DL
authors.lastname: Resnick
authors.affiliation: Department of Radiology, University of California San Diego Medical Center, 200 West Arbor Drive No. 8756, San Diego, CA, 92103, USA. mpathria@ucsd.edu.
authors.forename: Mini N
authors.initials: MN
authors.lastname: Pathria
mesh_terms: D000368:Aged; D002114:Calcinosis / Q000378:metabolism* / Q000473:pathology; D017886:Durapatite / Q000378:metabolism*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D057054:Molecular Imaging / Q000379:methods; D017006:Rotator Cuff / Q000378:metabolism* / Q000473:pathology; D012785:Shoulder Joint / Q000378:metabolism / Q000473:pathology; D052256:Tendinopathy / Q000378:metabolism* / Q000473:pathology; D014018:Tissue Distribution
chemical_list: D017886:Durapatite
keywords: Hydroxyapatite deposition disease; Intramuscular migration; Myotendinous junction; Rotator cuff