There has been considerable controversy over the years regarding the distinctions between various disorders characterized by a necrotizing and granulomatous inflammation of the tissues of the upper respiratory tract and oral cavity. It now seems clear that if infections and other known agents can be excluded, three clinicopathologic entities remain: Wegener's granulomatosis (a systemic disease), idiopathic midline (nonhealing) granuloma, and premalignant or malignant lymphoreticular lesions. The antigenic stimulus for all three may be related but remains unidentified.