The fine needle aspiration appearances of Kikuchi's lymphadenitis.

OBJECTIVE: To describe the fine needle aspiration cytological appearances of Kikuchi's lymphadenitis.

METHODS: Cytological review with histological correlation of all cases of Kikuchi's disease (KD) in which there had been an antecedent fine needle aspirate of the involved lymph node prior to lymph node excision between 2001 and 2006.

RESULTS: Twelve cases of KD were identified in which cytological and histological material was available. In eight cases the original prospective diagnosis of necrotizing non-granulomatous lymphadenitis consistent with KD had been suggested on the lymph node aspirate. Review of these cytological samples identified abundant extra- and intracellular apoptotic debris - the latter embedded in the cytoplasm of crescentic and phagocytic macrophages, set in a background reactive lymphoid population. Three of 12 cases were initially reported as in keeping with nonspecific reactive lymphadenopathy. Review identified intracellular apoptotic debris but no conspicuous extracellular nuclear debris. One case had originally been reported as possible non-Hodgkin's lymphoma. Histological review of the excised lymph nodes in all 12 cases showed the classical appearances of KD.

CONCLUSION: The accurate diagnosis of KD on fine needle aspiration is possible given correct clinical data, an adequately sampled and well-prepared specimen in which the characteristic intra- and extracellular apoptotic nuclear debris with admixed crescentic macrophages are identified on a reactive lymphoid background.