A case of cutaneous polyarteritis nodosa presenting with characteristic muscle Gadolinium ―enhanced MRI findings

Abstract

    The patient was a 34-year-old male. He visited our hospital for erythema, livedo reticularis,and arthralgia in November 2005.Skin biopsy revealed necrotizing vasculitis and a diagnosis of cutaneous polyarteritis nodosa (CPAN) was made. In March 2008, he was admitted to our hospital for myalgia in the left upper arm.
    There was an elevation of CRP but no rise of myogenic enzymes on admission. Autoantibodies, such as rheumatoid factor, antinuclear antibody, and anti-neutrophilic cytoplasm antibody were not detectable. Gadolinium ―enhanced MRI of the left upper arm showed an irregularity in the middle collateral artery and patchy areas of high intensity along the middle collateral artery in the triceps brachii muscle. These findings were considered to reflect vasculitis of CPAN and secondary edematous changes of the muscle. The patient was successfully treated with corticosteroids and MTX before being discharged. Gadolinium-enhanced MRI is useful to diagnose muscular lesions associated with vasculitis.