Kikuchi-Fujimoto disease in fine needle aspiration smears: a clinico-cytologic study of 18 pediatric cases and correlation with 68 adult patients.

OBJECTIVE Kikuchi-Fujimoto disease (KFD) is a self-limiting disorder which usually affects young women. There are only a few studies on pediatric KFD patients and their fine-needle aspiration (FNA) cytodiagnosis. We report a series of pediatric KFD patients diagnosed by FNA cytology and compare them with adults. MATERIALS AND METHODS By routine FNA cytology and through retrospective review smears initially diagnosed as reactive hyperplasia of lymph node during the years 2004-2009, 18 pediatric and 68 adult KFD cases were detected. The clinico-cytologic features of these two groups were compared. RESULTS The age of the pediatric patients ranged from 6 to 18 years with a median of 13.5 years and adult cases were aged 19 to 54 years with a median of 30 years. Only 1 pediatric case (5.6%) and 20 (29.4%) adult cases were initially diagnosed as KFD (P = 0.0604). Arab:non-Arab ratios were 4.3:1 among the pediatric patients and 1:1.5 for the adults (P = 0.0043). FNA smears were highly cellular in 4 (22.2%) pediatric cases and 37 (54.4%) adult cases (P = 0.0180). More than 5% Kikuchi histiocytes was present in 8 (44.4%) pediatric and 49 (72.1%) adult cases (P = 0.0474). No significant difference was observed in male: female ratio, frequency of head & neck lymphadenopathy, time (season) of presentation, and presence of neutrophils and capillary networks, etc. CONCLUSIONS Besides observation and interpretation errors, a significant difference between the two groups in respect of some clinico-cytomorphological features could have influenced the routine cytodiagnosis leading to lower pickup rate of pediatric KFD cases as compared to adults.