Kimura's disease is an important category of reactive lymphadenopathy in the Oriental population. The enlarged nodes are mostly located in the head and neck region. Salient pathological changes include florid germinal centers, Warthin-Finkeldey type polykaryocytes, vascularization of germinal centers, increased postcapillary venules in the paracortex, eosinophilic infiltration, and sclerosis. The pathology of Kimura's disease is quite different from that of angiolymphoid hyperplasia with eosinophilia (epithelioid hemangioma). Immunoperoxidase studies show IgE reticular networks in germinal centers. Nondegranulated surface IgE-positive mast cells are present in the paracortex. The authors propose that Kimura's disease represents an aberrant immune reaction to an as yet unknown stimulus. Although the individual histological features are nonspecific, the constellation of features is highly characteristic of Kimura's disease. Since lymphadenopathy can herald involvement of other tissues and the prognosis is excellent, accurate diagnosis of this disease in lymph node biopsies may spare the patients unnecessary radical surgery.