Fine Needle Aspiration

Fine needle aspiration (FNA) is a well-established minimally invasive technique for the cytologic evaluation of suspicious mass lesions involving lymph nodes and other organs. The 2008 WHO classification of tumors of hematopoietic and lymphoid tissues utilizes a multiparametric approach based on cytomorphologic, immunophenotypic, and cytogenetic features to classify these tumors (1). This approach can be applied to FNA cytologic specimens (2–8), of both nodal and extranodal sites. About 25% to 40% of lymphoid neoplasms arise outside of the lymph node system, and dissemination of nodal neoplasms may occur to almost any anatomical site, presenting as an extranodal mass (8). FNA in conjunction with flow cytometry (FCM) has been shown to be useful for the diagnosis and subclassification of lymphoma (2–4,8–10). The use of FNA for in the initial workup of patients with hematolymphoid neoplasms, particularly for patients who present with lymphadenopathy, remains underutilized (Table 12.1). Lymphoma constitutes approximately 10% of cases diagnosed by FNA (2,7,9–11).