[Kikuchi disease]

Histiocytic necrotizing lymphadenitis or Kikuchi-Fujimoto disease (KFD) was described in 1972. Painful, palpable lymphadenitis is localized to one or two sites in the head and neck territories in young adults (third decade) and is associated with fever. Other clinical manifestations are infrequent: arthromyalgias, cutaneous rash, sweating, splenomegaly. Leukopenia is present in 50% of the cases with sometimes "atypical" lymphocytes. A spontaneously favorable outcome is noted after a mean 3 months. Histopathology of the lymph node is the key for the diagnosis of KFD showing lymph node necrosis of 25 to 75% of the surface, in the cortex and the medulla of the lymph nodes with histiocytic proliferation and plasma cells. Histochemistry shows positive straining for monocytic markers (CD68+, KiM1P+). Alpha-beta CD8+ T cells are abundant, NK and B cells are scarce. Pathological examination enables to differentiate KFD from other types of necrotizing lymphadenitis (SLE, malignant lymphoma, pyogenic infections). Kikuchi disease can be the result of local hyperimmune stimulation after viral, bacterial or parasitic infection. CD4+ cells would then become apoptotic cells. In some cases KJD is associated with systemic diseases such as systemic lupus erythematosus or adult Still's disease.