Kikuchi-Fujimoto disease: an uncommon cause of neck swelling.

Kikuchi-Fujimoto's disease (KFD) is a rare, benign condition characterized by histiocytic necrotizing lymphadenitis predominantly in the cervical region and prolonged fever. It has a higher prevalence in the Japanese and Asian populations although it may be seen in a wide geographic distribution, but rare are the cases reported in Europe. While symptoms resolve spontaneously between 2 weeks and 2 months, complications are described in: CNS, eyes, respiratory tract, kidney and liver. KFD also described an association with systemic lupus erythematosus. This paper describes a rare case of Kikuchi-Fujimoto lymphadenitis and discusses the features of the disease. A 24-year-old man presented with fever and a swollen 3-cm lymph node in the left side of the neck. The definitive diagnosis was established, after excision of level VB nodes on the left, by histologic examination. It revealed structurally intact tissue with scalloping in the paracortical area presenting activated T cells, focal monocytoid B cells, sinus histiocytosis and normally polarized follicles. Other two samples presented focal alterations of the tissue structure due to broad areas of necrosis, conspicuous nuclear debris, large lymphoid cells as well as numerous histiocytes. Immunohistochemistry revealed CD3+ and CD8+ T lymphocytes and histiocytes expressing CD68/PGM-1 (specific for macrophage lineage) and myeloperoxidase (MPO, specific for myeloid lineage). Correct, prompt diagnosis should be established through the findings of imaging and pathologic studies to avoid unnecessary investigation and ineffective therapies.