Fine Needle Aspiration Cytology of Kikuchi-Fujimoto’s Disease: A Report of 2 Cases with Emphasis on Cytologic Features and Differential Diagnosis

Abstract

Background: Kikuchi-Fujimoto’s disease (KFD) or histiocytic necrotizing lymphadenitis is an uncommon, benign, self-limited disease of unknown etiology, primarily affecting young women. Herein, we present the cytologic features of KFD of 2 cases that presented with different clinical pictures and discuss the cytologic differential diagnosis of this condition. Cases: Case 1 was a 17-year-old girl who presented with cervical lymphadenopathy since 6 weeks and case 2 was a 32-year-old female who had cough and axillary lymphadenopathy since 8 weeks. The fine needle aspiration (FNA) smears of both cases revealed a polymorphous lymphoid population intermingled with histiocytes, many of which showed a small size, eccentric location, crescent-shaped nuclei and abundant karyorrhectic debris in the background. A diagnosis of histiocytic necrotizing lymphadenitis was made on FNA cytology, which was confirmed by subsequent histologic examination of the lymph nodes. Conclusion: Precise diagnosis of KFD on cytologic smears is crucial as it can be mistaken for tuberculous lymphadenitis, systemic lupus erythematosus, malignant lymphoma or even metastatic carcinoma, and to avoid unnecessary investigations and potentially harmful treatment. With adequate, well-preserved samples and appropriate clinical setting, the presence of abundant karyorrhectic debris, crescentic macrophages, a polymorphous lymphoid population and absence of epithelioid cell granulomas, giant cells and neutrophils must alert the cytopathologist to arrive at a correct diagnosis.