The diagnosis and classification of vasculitic syndromes in general requires a correlation of clinical histologic and serologic data. Classifications based solely on clinical or histologic features have proven unsatisfactory. WG is no exception, and proper diagnosis and management of patients with WG requires careful correlation of all available clinical, radiographic, serologic, and histologic data by experienced individuals. Active discourse between the clinician and pathologist frequently helps in the decision as to how to proceed in an individual case and whether or not further diagnostic tests are necessary.