Clinicopathological review of immunohistochemically defined Kikuchi-Fujimoto disease-including some interesting cases.

Kikuchi-Fujimoto Disease (KFD) is a benign, self-limited disease characterized by tender regional lymphadenopathy with fever. KFD remains a poorly defined disease, and no clear diagnostic criteria are available. Here, we assess the clinical, laboratory, and histopathologic findings of KFD cases and report two unusual cases. Forty KFD patients that underwent lymph node (LN) biopsy and diagnosed by immunohistochemical staining, from January 2003 to November 2010, were enrolled in this retrospective study. The patients had a mean age of 29.3 years, and 29 (72.5 %) were women. Affected LNs were mainly located unilaterally in the cervical area. Mean LN size was 15.3 mm. Twenty-eight (70 %) patients had LN tenderness, and 25 (62.5 %) patients had fever. Leukopenia was observed in 18 of 35 evaluable patients. C-reactive protein and erythrocyte sedimentation rate were elevated in most patients. Anti-nuclear antibody was positive in four of 19 evaluable patients, but all had been diagnosed with concurrent systemic lupus erythematosus. Histologically, the 40 cases were classified into three types, that is, as proliferative (37.5 %), necrotizing (55.0 %), or xanthomatous (7.5 %). Interesting cases: Case 1 was a 35-year-old female with KFD and uveitis, retinal vasculitis, and superior sagittal sinus thrombosis. Case 2 was a 47-year-old male with KFD and bone marrow involvement and presented with severe bicytopenia. Although KFD is an uncommon self-limited benign disorder, it must be included in the differential diagnosis of lymphadenopathy with fever and cytopenia. It is important that the clinical features of KFD be understood to reach a correct diagnosis.