Kikuchi-Fujimoto disease (KFD) is a histiocytic necrotizing lymphadenitis found mainly in young women. Patients typically present with cervical lymphadenopathy and fever and follow almost always a benign course with excellent outcomes. The etiology of KFD remains unknown and controversial although several viruses have been associated with this disease. One theory proposes that KFD may be a self-limiting form of systemic lupus erythematosus (SLE). This theory is strongly supported by the fact that microscopic features of KFD can be very similar to those found in lupus lymphadenitis. Despite its usually benign course, several cases with fatal outcomes have been reported. We report here a case of clinically aggressive KFD, which featured several autoimmune-related events and resulted in a fatal outcome. Autopsy studies showed characteristic findings of SLE, which suggests a remarkable link between SLE and KFD. Early and intensive immunosuppressive treatment may be the only option for patients who develop very aggressive forms of KFD in order to avoid a fatal outcome.