Cutaneous lymphocytic thrombophilic (macular) arteritis: a distinct entity or an indolent (reparative) stage of cutaneous polyarteritis nodosa? Report of 2 cases of cutaneous arteritis and review of the literature.

Recently, 2 putatively novel clinicopathological entities, macular arteritis (MA) and lymphocytic thrombophilic arteritis (LTA), have been described. Both exhibit an indolent chronic course and erythematous and hyperpigmented macules (MA > LTA) and papules/plaques (LTA > MA), often in a reticulated pattern on the lower limbs. Histopathologically, they show varying degrees of lymphocyte infiltration and disruption of the arterial wall, concentric luminal fibrin deposition, and in some cases, fibrointimal scarring (endarteritis obliterans). This spectrum of histology overlaps with the subacute, reparative, and healed stages reported for cutaneous polyarteritis nodosa (CPAN). Herein, we report 2 cases of cutaneous lymphocytic arteritis, 1 with persistent indolent disease and the second with acute self-limited disease. Comparing these 2 patients' findings with that reported for MA, LTA, and CPAN highlights a clinicopathologic spectrum, which exhibits increasing disease severity moving from MA to LTA to CPAN to systemic polyarteritis nodosa. Given the clinicopathologic similarities, we conclude that our cases and cases previously reported as MA or LTA likely represent an indolent form of CPAN.