Cytologic findings of angioimmunoblastic T-cell lymphoma: analysis of 16 fine-needle aspirates over 9-year period.

BACKGROUND

Peripheral T-cell lymphoma often represents an important diagnostic pitfall in fine-needle aspiration biopsy due to the heterogeneous cell population present. A classic example of this group is angioimmunoblastic T-cell lymphoma (AILD-T). The fine-needle aspiration cytology of this relatively well-defined histologic subtype of T-cell lymphoma is rarely described in the literature.

METHODS

The authors reviewed 16 fine-needle aspirates of AILD-T from 9 patients in Queen Mary Hospital and Pamela Youde Nethersole Eastern Hospital, Hong Kong, over a 9-year period from early 1993 to mid-2001. The morphologic features seen in cytology smears and/or cell block sections were correlated with histologic and immunohistochemical findings of excisional biopsy specimens.

RESULTS

The smears and cytospin preparations showed a heterogeneous population of hematolymphoid cells, including small lymphocytes; nondescript, medium-sized lymphoid cells; immunoblasts; plasma cells; eosinophils; and reticulum cells, including follicular dendritic cells. In general, tingible body macrophages were not identified. Conversely, follicular dendritic cells were discernible easily in most cases and sometimes were admixed intimately with lymphoid cells, forming dendritic cell-lymphocyte complexes. There also were large lymphoid tissue fragments containing a scaffold of arborizing small vessels. Pleomorphic cells with high mitotic activity or lymphoid cells with clear cytoplasm were not identified. The cell block sections often showed an intimate admixture of small lymphocytes, plasma cells, eosinophils, and reticulum cells amid a background of reticulin fibers. Lymphoid follicles with well-developed germinal centers were never found. The features seen in cytologic preparations were reminiscent of those seen in histologic sections of the corresponding lymph node excisional biopsies.

CONCLUSIONS

though ancillary investigative methods, including flow cytometry and molecular study, are of limited value in fine-needle aspiration cytology assessment of AILD-T due to the heterogeneous cell population present, recognition of the peculiar combination of cytologic features, especially in the right clinical setting, should provide a clue about the diagnosis. A high index of suspicion is essential to avoid a false negative diagnosis of reactive lymphadenopathy.