MR imaging findings of focal myositis: A pseudotumour that may mimic muscle neoplasm

Michele Gaeta, Silvio Mazziotti, Fabio Minutoli, Antonino Genitori, Antonio Toscano, Carmelo Rodolico, Alfredo Blandino

Research output: Contribution to journalArticlepeer-review


Objective: The authors describe magnetic resonance (MR) findings in eight patients with histologically confirmed focal myositis. Materials and 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. Conclusion: Focal myositis is an uncommon pseudotumour which should be considered in the differential diagnosis of muscular masses and myopathies.

Original languageEnglish
Pages (from-to)571-578
Number of pages8
JournalSkeletal Radiology
Issue number6
Publication statusPublished - Jun 2009


  • Magnetic resonance imaging
  • Muscles
  • Myositis
  • Pseudotumour

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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