Polyarteritis manifesting as calf myositis and fever

A patient presented with fever of undetermined cause for two months. On physical examination, bilateral calf tenderness was elicited, prompting a diagnostic muscle biopsy for polyarteritis. This limited form of polyarteritis is reviewed in the context of this case and previously reported cases. Polyarteritis limited to muscle seems to have a good prognosis and responds readily to steroids alone.