Cutaneous lymphocytic thrombophilic (macular) arteritis.

Macular arteritis (MA) has a striking discordance between the clinical presentation of hyperpigmented macules and the histopathologic findings of a lymphocytic arteritis with intraluminal hyalinized fibrin ring and thrombosis. It has been proposed that MA represents the chronic, indolent, lymphocytic form of the neutrophil-predominant cutaneous polyarteritis nodosa. MA usually affects middle-aged women asymptomatically on the legs. There is also a slightly more severe variant with more infiltrated plaques and livedo racemosa, termed lymphocytic thrombophilic arteritis. MA and lymphocytic thrombophilic arteritis have similar histologic features, both with a largely intact vascular elastic lamina, despite the abundant fibrin and endarteritis obliterans. There is no evidence for progression from MA to lymphocytic thrombophilic arteritis to cutaneous polyarteritis nodosa, and aggressive therapy should be avoided in MA, given the indolent, benign disease course.