Introduction. Vasculitis.

The vasculitides commonly create diagnostic and management problems, and a biopsy diagnosis of vasculitis usually does not stand alone in the proper medical management of a patient. Indeed, a conclusive diagnosis usually cannot be made without correlation with the patient's clinical history, physical findings, and/or angiographic findings. Nonetheless, a definitive diagnosis depends on histologic examination because few vasculitic syndromes have specific clinical and laboratory findings. Moreover, the histopathologic diagnosis depends on pathologist experience, tissue selection, sample size, chronologic age of the biopsied lesion(s), and effects of prior treatment. In this issue of Seminars in Diagnostic Pathology the important systemic vasculities are reviewed and updated. These include: polyarteritis nodosa, microscopic polyangiitis (microscopic polyarteritis), cutaneous leukocytoclastic vasculitis, Wegener's granulomatosis, giant-cell vasculitides, localized vasculitis, and angiocentric lymphomas (lymphomatous vasculitis).