Spectrum of morphologic changes in lymph nodes attributable to fine needle aspiration.

Fine needle aspiration biopsy (FNAB) is a commonly used diagnostic tool for the investigation of lymphadenopathy, but little has been written about the morphologic changes resulting from this procedure and whether these changes interfere with subsequent histologic assessment. We therefore reviewed the histologic sections of a consecutive series of lymph node biopsies with previous FNAB. Ten out of 230 such cases showed changes attributable to FNAB. In four cases, hemorrhage accompanied by various stages of organization was seen, with a linear needle tract being identified in two of them. Proliferation of spindle cells around the hemorrhagic foci could raise a concern for Kaposi's sarcoma. Three cases showed segmental infarction of the nodal parenchyma, characterized by a wedge-shaped area of lymphocyte depletion and hemorrhage. Three cases showed total coagulative necrosis, which was attributable to the effects of FNAB rather than to spontaneous occurrence because the aspirates yielded abundant viable large atypical lymphoid cells. These three cases of total infarction were proven to be large-cell lymphoma upon subsequent biopsies. We conclude that the FNAB procedure may rarely affect histologic assessment of lymph nodes when there is florid myofibroblastic proliferation or total infarction. The latter complication is more likely to occur in lymph nodes involved by malignant lymphoma.