[Macular lymphocytic arteritis and periarteritis nodosa: A case report showing diagnostic and nosological challenges posed by these two entities].

BACKGROUND: Macular lymphocytic arteritis is a recently described type of cutaneous vasculitis involving vessels of medium size. Authors consider it as a form of polyarteritis nodosa. Herein we report a case of macular lymphocytic arteritis during the course of which periarteritis nodosa appeared.

PATIENTS AND METHODS: A 50-year-old man, with no history other than chronic venous insufficiency of the lower limbs, presented with an asymptomatic eruption involving all four limbs, mainly the lower limbs, and appearing in episodes. Physical examination revealed brown macules, in some cases outlining the configuration of livedo reticularis. Laboratory findings were normal except for the presence of low levels of anticardiolipin activity at diagnosis, which had subsided three months later. Histological examination of the skin biopsy showed lymphocytic arteritis with some histiocytes and neutrophils, as well as an eosinophilic ring of parietal necrosis. Six months later, the patient developed multineuritis, leading to the diagnosis of polyarteritis nodosa. A diagnosis of cutaneous polyarteritis nodosa could also have been made based on the association of cutaneous livedo and locoregional polyneuritis without systemic involvement.

DISCUSSION: The diagnosis of macular lymphocytic arteritis is based upon clinical and histological findings and upon disease progression. This entity seems to belong to the same spectrum as periarteritis nodosa, especially in the cutaneous form. Given the lack of knowledge concerning progression from macular lymphocytic arteritis to nodosa periarteritis, close patient monitoring is called for, as illustrated by our case report.