Benign non-infectious causes of lymphadenopathy: A review of cytomorphology and differential diagnosis.

Fine-needle aspiration (FNA) biopsy is a quick, cost-effective, and safe diagnostic modality that provides answers to guide treatment and management in patients with lymphadenopathy. In adults and children, there are a range of non-neoplastic, non-infectious etiologies for lymphadenopathy. These include reactive lymphoid hyperplasia (RLH), dermatopathic lymphadenitis (DLN), Rosai-Dorfman disease, Castleman disease, Kimura disease, Kikuchi-Fujimoto disease, and lymphadenopathy associated with autoimmune and metabolic/storage disease. Other benign nodal entities that may be encountered include lymph node infarction, foreign body reactions, drug reactions, extramedullary hematopoeisis, and benign inclusions. This article reviews the practical role of FNA in the evaluation of these benign, non-infectious causes of lymphadenopathy and focuses on their cytomorphology and differential diagnosis.