title: Role of repeat skeletal muscle biopsy: how useful is it?
abstract: BACKGROUND
  The role of skeletal muscle biopsy is established; however, to our knowledge, no study has systematically evaluated the utility of a repeat biopsy.
  
  
  METHODS
  This study was a retrospective clinicopathologic review of 66 patients (mean age 38.1 years, 39 men) with at least 1 repeat muscle biopsy obtained between February 1992 and November 2011. Clinical data determined how results of the subsequent biopsy impacted patient management.
  
  
  RESULTS
  Repeat biopsy yielded a definitive diagnosis in 16 of 66 patients (24%). In the remaining patients, a repeat study provided clinically useful information or directly answered the clinical question (n = 30, 45%) by excluding a differential consideration (n = 19), supporting treatment continuation (n = 8), prompting treatment change (n = 1), confirming the original diagnosis (n = 1), or establishing a likely diagnosis (n = 1).
  
  
  CONCLUSIONS
  Repeat muscle biopsy plays a role in the evaluation of patients with suspected myopathy in certain clinical circumstances.
authors.affiliation: Neuromuscular Center, Cleveland Clinic, Cleveland, Ohio, USA. sgoutman@med.umich.edu
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Goutman
authors.forename: Richard A
authors.initials: RA
authors.lastname: Prayson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001706:Biopsy / Q000706:statistics & numerical data; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000473:pathology*; D009135:Muscular Diseases / Q000473:pathology*; D012189:Retrospective Studies; D055815:Young Adult