Kikuchi-Fujimoto necrotizing lymphadenitis. Report of two cases.

Kikuchi-Fujimoto disease (KFD) is a form of necrotizing lymphadenitis. The disease is a usually benign, self limited cause of lymph node enlargement affecting predominantly young women. Several other clinical manifestations have been described, though the only consistent findings are a macular eruption and a fever. Occasionally, the disease has presented as a fever of unknown origin. Lymph node specimens show areas of necrosis without neutrophilic infiltration. Lymphocyte mediated apoptotic mechanisms are responsible for the necrosis observed. Clinically, it should be differentiated from many different conditions, including infections such as cat scratch disease and rheumatological diseases like Still's disease and Systemic Lupus Erythematosus. Pathologically, it should be differentiated from lymphomas. KFD is widely known in the Far East, but very rare in Latin America. As a matter of fact, we have only detected four reported cases from Argentina, Brasil and Chile. We here describe two additional cases from Argentina. Both occurred in young women. One had a mediastinal compromise and a recurrent course, only observed in 4% of cases. The second one had a classical cervical presentation. The diagnosis in both was made by lymph node biopsy, although, in areas of great prevalence, an aspiration may be sufficient to establish the disease. We anticipate that the real prevalence of this unusual disease is highly underrepresented.