[Kikuchi-Fujimoto disease mimicking malignant lymphoma in adolescents]. / La maladie de Kikuchi-Fujimoto ; un diagnostic différentiel méconnu du lymphome chez l'adolescent.

Kikuchi-Fujimoto disease, also known as histiocytic necrotizing lymphadenitis, is a rare cause of lymphadenopathy in children. This benign disease can mimic lymphoma and misleads doctors. It was first described in Asia, where it occurred especially in young women. Recent publications show that it can also affect teenagers and young adults in Caucasian populations. The pathophysiology remains unknown. Three hypotheses have been raised for this disease: the role of viruses (in particular HHV-8), genetic predisposition (two alleles in HLA class II genes were found more frequently in patients with Kikuchi disease), and an autoimmune cause because of the correlation with lupus erythematosus. Few cases have been reported in Europe so far. In this article, we report three cases of Kikuchi disease observed in less than 2 months in a single hospital in France. All three patients were teenagers who presented with lymphadenopathy, either isolated or combined with fever, weakness, and weight loss. In all of them, the hypermetabolic activity of the lymph node on the PET scanner misled us to suspect lymphoma. The diagnosis of Kikuchi disease was finally made, for all patients, after 2 weeks in the hospital based on lymph node biopsy. Based on this report, we highlight that early biopsy in presence of lymphadenopathy can avoid unnecessary extensive investigations. Moreover, in this rare disease, it is very surprising to come across three cases that are not family-related, in such a short period of time. This strengthens the hypothesis of the possible implication of an environmental factor in the pathophysiology of Kikuchi disease.

Bacillus Calmette-Guérin infection after vaccination of human immunodeficiency virus-infected children.

The use of Mycobacterium bovis/Bacillus Calmette-Guérin (BCG) to vaccinate against tuberculosis remains controversial. The development of tuberculosis in human immunodeficiency virus (HIV)-infected children demands specific evaluation of the risk/benefit ratio of BCG vaccination in this situation. In our institution 9 of 68 HIV-infected children vaccinated with BCG before the diagnosis of HIV infection was suspected developed vaccine-related complications: 7 of these children had a large satellite adenopathy with or without skin fistulae, whereas the other 2 had disseminated BCG infection beyond the satellite ganglion (involvement of the spleen and mesenteric and mediastinal lymph nodes in one case and the liver and lungs in the other). The children were vaccinated soon after birth; no particular problems were observed at that time, but complications appeared 3 to 35 months later. All but one of these children had a rapidly progressive form of HIV disease. The possibility of delayed local or disseminated BCG infection must be considered in analysis of the risk/benefit ratio of vaccination of HIV-infected children. The prognosis of HIV infection must be taken into account, even if the child is asymptomatic when vaccination is being considered.