Polymyositis Beginning as a Focal Process

Focal Myositis in paediatric age

“…Age ranged from 7 to 94 years (mean 41, median 36 y) and only 2 cases were younger than 10 years of age. Clinically FM presents as swelling or enlarging of a skeletal muscle, typically moveable and unattached to the overlying intact skin with little or no pain and minimal systemic symptoms or signs, which differentiates it from an early, localised form of polymyositis 4 . The inferior limbs are tipically involved and FM has also been described in many other unusual sites including the tongue 5 , eyelid 6 and oesophagus 7 .…”

Grand Rounds--University Hospital of Wales: Focal myositis mimicking acute psoas abscess

“…The patient's muscle disease would fulfil the criteria for “probable polymyositis” as defined initially by Bohan and Peter8 and later by Dalakas,6 but the acute multifocal, asymmetrical onset with spontaneous remission and subsequent relapses is very atypical. A few cases of polymyositis have been described in which the initial presenting features were those of focal muscle inflammation,9 10 11 although none of these patients to our knowledge subsequently developed systemic lupus erythematosus. Focal myositis usually presents as a solitary, painful, rapidly enlarging muscle mass with no associated systemic features or laboratory abnormalities 12 13.…”

Focal myositis associated with S‐1 radiculopathy: Report of two cases

“…Systemic symptoms are typically absent and serum muscle enzymes or other routine laboratory investigations are normal. 12,15,17 Computerized tomography reveals a well-circumscribed lesion, isodense with muscle tissue, and T2-weighted MRI shows increased signal intensity within the entire head of the muscle, sometimes with fatty infiltration and inhomogeneous enhancement after contrast. 6,7 These aspects can simulate a soft tissue neoplasm, but the diagnosis of local inflammation is confirmed by biopsy.…”