[Polyarteritis nodosa cutanea: a case report].
Cutaneous vasculitides continue to be difficult to diagnose and treat because of the complexity of these disorders. Current classification schemes are based on clinical findings and histopathologic criteria, so biopsy of an early evolving lesion is the most effective means of establishing the diagnosis. We describe the case of a 74 years old man suffering from livedo reticularis and painful nodular lesions, with ulcers, on the legs. Establishing a precise diagnosis has required biopsy of the lesions which showed histopathologic feature of cutaneous polyarteritis nodosa and the designation of cutaneous vasculitis as "isolated" or "primary" was based on lack of systemic disease documented by clinical findings, laboratory tests and instrumental investigations. Remission occurred after moderate doses of steroid therapy and after a year of management with low dose of steroid therapy the patient experienced significant improvement. Cutaneous polyarteritis nodosa is usually a benign disease, however it may relapse, and a long range follow up of the patient is necessary because of the possibility of systemic involvement.