ABSTRACT
BACKGROUND: Microscopic polyarteritis is a systemic small-vessel vasculitis that primarily involves the kidneys but may also affect the skin and other organ systems. This unique vasculitis represents one of the vasculitides with antineutrophil cytoplasmic antibodies, usually of the perinuclear immunostaining pattern (P-ANCA, antimyeloperoxidase antibodies). The objective of this case report is to describe microscopic polyarteritis, the use of antineutrophil cytoplasmic antibodies, and the unique cutaneous histopathologic features of our patient. OBSERVATIONS: We describe a patient with clinical findings consistent with microscopic polyarteritis, the presence of antimyeloperoxidase antibodies, and a specific cutaneous leukocytoclastic vasculitis. This report further characterizes the histopathologic features by demonstrating that the anatomic location of the cutaneous vasculitic lesions is at the level of the dermal arteriolar vessels and postcapillary venules. CONCLUSIONS: Cutaneous arteriolar leukocytoclastic vasculitis may prove to be a histologic hallmark of microscopic polyarteritis when it presents in the skin. However, further case comparisons and histopathologic investigations are needed. The consequences of this systemic vasculitis, if not adequately treated, may be life threatening. Recognition of clinical features, use of antineutrophil cytoplasmic antibodies, and demonstration of a cutaneous arteriolar leukocytoclastic vasculitis may aid in the diagnosis and subsequent treatment of patients followed up by dermatologists for vasculitic ulcers.
