Thirty-six cases of necrotizing lymphadenitis--including 33 cases of unknown etiology, 1 typhoid lymphadenopathy, and 2 cases of suspicious lupus lymphadenopathy--were clinico-pathologically reviewed and analyzed with immunostaining for s-100 and lysozyme. All cases histologically showed architectural effacement by paracortical lesions composed of nuclear karyorrhexis and mononuclear cell proliferation. Immunohistochemical study revealed proliferation of lysozyme-positive macrophages in the necrotizing areas and an increase in the number of s-100-positive cells in the uninvolved paracortical areas. This observation suggests that necrotizing lymphadenitis may be a common morphologic expression of a T cell-mediated hyperimmune condition induced by diverse etiologies.