Kikuchi-Fujimoto disease, or histiocytic necrotizing lymphadenitis, is a self-limited condition, characterized by benign lymphadenopathy with associated fevers and systemic symptoms. It most commonly affects adults younger than 40 years of age and of Asian descent. Involved lymph nodes demonstrate paracortical areas of apoptotic necrosis with abundant karyorrhectic debris and a proliferation of histiocytes, plasmacytoid dendritic cells, and CD8(+) T cells in the absence of neutrophils. Kikuchi-Fujimoto disease is thought to have 3 evolving phases: proliferative, necrotizing, and xanthomatous. The etiology is unknown, although viruses and autoimmune mechanisms have been proposed. No specific laboratory tests contribute to the diagnosis. Diagnosis requires histopathologic examination and exclusion of other factors by ancillary studies. Non-Hodgkin lymphoma and systemic lupus erythematosus should be ruled out before diagnosis of Kikuchi-Fujimoto disease, given the overlapped clinical and histologic features as well as the different therapeutic approaches. Treatment involves supportive measures, and the symptoms usually resolve spontaneously within 4 months.