Necrotizing lymphadenitis: a review of clinicopathological, immunohistochemical and ultrastructural studies.

Necrotizing lymphadenitis (NEL) has been reported to be a reactive process described under differing terminology by Fujimoto et al. (1972), Kikuchi (1972), Wakasa et al. (1973) and other Japanese pathologists. Recently, this type of lymphadenitis has also been reported in America and Europe. In Japan, NEL is observed more frequently in the northern area, however, no characteristic seasonal occurrence has been noted. The disease affects young females more than males, particularly from the third and fourth decades onwards. Common cold-like symptoms, lymphadenopathy of the cervical region and leukopenia are characteristic clinical findings in the early stages. Morphological features of the involved lymph nodes include the presence of numerous immunoblasts, histiocytes and macrophages, the latter with phagocytized nuclear debris derived from degenerated lymphocytes. However, granulocytes are generally absent. Tubular inclusions are observed ultrastructurally. Immunohistochemical studies of peripheral blood using monoclonal antibodies have revealed that the helper/suppressor (Leu 3a/2a) ratio increases gradually with the clinical course because of a decrease in Leu 2a + cells. The pathogenesis of NEL is uncertain, but it has been speculated that there is cytolytic infection of lymphocytes by a virus or other organism, accompanied by secondary blastic transformation of suppressor T-lymphocytes.