title: MR imaging findings of focal myositis: a pseudotumour that may mimic muscle neoplasm.
abstract: OBJECTIVE
  The authors describe magnetic resonance (MR) findings in eight patients with histologically confirmed focal myositis.
  
  
  METHODS
  In each patient, axial TSE T1-weighted and fast short-tau inversion recovery (STIR) images were obtained using a 1.5-T MR scanner. Three patients also underwent dynamic contrast-enhanced MR examination using a GE T1-weighted sequence. The following features were evaluated: anatomical distribution, extent of the involvement, signal intensity characteristics, dynamic enhancement pattern and outcome at follow-up examinations.
  
  
  RESULTS
  Seven of eight lesions were located in the lower extremities, one of eight in the arm; four of eight involved part of a muscle, two of eight diffusely involved a muscle and two of eight showed multifocal involvement of two or more muscles. All lesions were hyperintense on fast-STIR images: the hyperintensity was homogeneous in six of eight and inhomogeneous in two of eight. On T1-weighted unenhanced images, all lesions but two appeared isointense or slightly hypointense in comparison to normal muscles; two lesions showed a slight hyperintensity. Dynamic enhancement pattern corresponded to the type usually seen in benign soft tissue lesions. All lesions disappeared.
  
  
  CONCLUSIONS
  Focal myositis is an uncommon pseudotumour which should be considered in the differential diagnosis of muscular masses and myopathies.
authors.affiliation: Department of Radiological Sciences, University of Messina, AOU Policlinico G Martino, Messina, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Gaeta
authors.forename: Silvio
authors.initials: S
authors.lastname: Mazziotti
authors.forename: Fabio
authors.initials: F
authors.lastname: Minutoli
authors.forename: Antonino
authors.initials: A
authors.lastname: Genitori
authors.forename: Antonio
authors.initials: A
authors.lastname: Toscano
authors.forename: Carmelo
authors.initials: C
authors.lastname: Rodolico
authors.forename: Alfredo
authors.initials: A
authors.lastname: Blandino
mesh_terms: D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019042:Muscle Neoplasms / Q000473:pathology*; D018482:Muscle, Skeletal / Q000473:pathology*; D009220:Myositis / Q000473:pathology*; D055815:Young Adult