Polyarteritis nodosa confined to calf muscles.

Two patients who developed pain and tenderness in their calf muscles, without other organ system involvement, are described. A gastrocnemius biopsy disclosed necrotizing muscular arteritis. Five other reported cases are reviewed and we conclude that there is a limited form of polyarteritis nodosa localized to calf muscles, with a differentiated and more benign clinical course, a differential diagnosis restricted to local pathological processes and prompt response to treatment with corticosteroids alone.