Kikuchi-Fujimoto disease in fine-needle aspiration smears: a clinico-cytologic study of 76 cases of KFD and 684 cases of reactive hyperplasia of the lymph node.

Kikuchi-Fujimoto disease (KFD) is cytologically characterized by a polymorphous lymphoid cell population, abundant karyorrhectic debris and histiocytes, many of which are crescentic (Kikuchi histiocytes). As per reviewed literature, KFD may be confused with tuberculosis, lymphoma, and reactive hyperplasia of lymph nodes (RHLN). Since RHLN was found to be a major challenging factor during routine cytodiagnosis of KFD in our material, we tried to find out the differentiating clinico-cytologic features between 76 KFD and 684 RHLN cases seen in Kuwait. 63.2% of KFD were in 3rd and 4th decades of life as compared to 40.2% of RHLN (P = 0.0002). Male to female ratio was 1: 2.45 for KFD and 1:1.09 for RHLN (P = 0.0022). Kuwaiti:non-Kuwaiti ratio was 1:2.04 for KFD and 1.31:1 for RHLN (P < 0.0001). Capillary networks was present in 71.1% of KFD smears and 52.6% of RHLN (P = 0.0023). Tingible body macrophages and dendritic reticulum cells were detected in 17.1% and 22.4%, respectively, in KFD as opposed to 50.1% and 58.8%, respectively, in RHLN (P < 0.0001). Kikuchi histiocyte count ranged from 2 to 36% in KFD and was ≥10% in 31 (40.8%). Rare Kikuchi histiocytes were detected in 16 (2.3%) of RHLN cases but in none of them the count exceeded 1%, whereas their count was >1% in all KFD cases (P < 0.0001). Thus, KFD cases differed significantly from RHLN in respect of age and sex distribution, Kuwaiti:non-Kuwaiti ratio, and cytomorphologic features such as capillary networks, Kikuchi histiocyte count, dendritic reticulum cells, and tingible body macrophages.