title: Rheumatoid myositis, myth or reality? A clinical, imaging and histological study.
abstract: Rheumatoid myositis (RM) is still poorly characterized, albeit the concept of muscle involvement in rheumatoid arthritis (RA) is well-recognized as being driven by a wide range of causes including inflammation, drugs, impaired joint flexibility, sedentarism.
  
  
  OBJECTIVE
  To describe clinical, serological, imaging and histological pattern of RM.
  
  
  METHODS
  This is a retrospective study on eight RM selected from a cohort of one hundred and three RA systematically assessed for skeletal muscle involvement. Data collected included clinical, serum muscle enzymes, muscle imaging and biopsy (Hematoxylin-Eosin, modified Gömöri trichrome staining).
  
  
  RESULTS
  Routine muscle histology indicated both non-specific muscle fiber damage (changes in fiber size and internal structure: pleomorphic mitochondria, dilated sarcotubular system, multiple internal or subsarcommal nuclei; abnormal fiber types distribution: trend towards type II; atrophy; degenerative/regenerative modifications) and the presence of inflammatory deposits in all patients (mild to moderate, patchy B- and T-cells infiltrates, mainly perivascular and endomysial, but also in the perimysial region classified as polymyositis-like deposits). High levels of serum muscle enzymes, abnormal EMG (short duration, small amplitude, polyphasic motor unit action potentials) without insertional activity and fibrillations, active inflammation on both Doppler ultrasound and MRI were commonly reported.
  
  
  CONCLUSIONS
  Traditional analysis of muscle biopsy specimens (Hematoxylin-Eosin, modified Gömöri trichrome staining) is faraway unsatisfactory, only documenting changes in muscle fibers size, architecture, internal structure, and, possibly, detecting perivascular, perimysial or endomysial inflammatory deposits. Upcoming research should address the value of muscle imaging for the diagnosis and evaluation of treatment response and muscle function in rheumatoid myositis.
authors.affiliation: "Grigore T. Popa" University of Medicine and Pharmacy, Iassy, Romania; emil.anton@yahoo.com.
authors.forename: Codrina
authors.initials: C
authors.lastname: Ancuţa
authors.forename: Daniela Cristina
authors.initials: DC
authors.lastname: Pomîrleanu
authors.forename: Carmen Rodica
authors.initials: CR
authors.lastname: Anton
authors.forename: Eovelina
authors.initials: E
authors.lastname: Moraru
authors.forename: Emil
authors.initials: E
authors.lastname: Anton
authors.forename: Rodica Marieta
authors.initials: RM
authors.lastname: Chirieac
authors.forename: Eugen
authors.initials: E
authors.lastname: Ancuţa
mesh_terms: D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis* / Q000473:pathology*; D001706:Biopsy; D057645:Deltoid Muscle / Q000473:pathology; D005260:Female; D006801:Humans; D007249:Inflammation / Q000473:pathology; D008297:Male; D008875:Middle Aged; D018485:Muscle Fibers, Skeletal / Q000473:pathology; D009220:Myositis / Q000097:blood / Q000175:diagnosis* / Q000473:pathology*