Plasmablastic lymphoma: Cytologic findings in 5 cases with unusual presentation

Plasmablastic lymphoma (PBL) is a rare form of non-Hodgkin lymphoma that was once believed to occur primarily in the oral cavity of human immunodeficiency virus-positive individuals. Numerous extraoral sites have also been reported to date. To the authors' knowledge, however, only 3 reports in the literature describe its cytologic features. In the current study, the cytologic findings in 5 additional patients are reported, 3 of whom had concomitant second malignancies. The goal of the current study was to define the cytomorphologic features that may help to distinguish PBL from other mimics.

Five cases were identified from the pathology files for which cytology was available. The presence of the following was evaluated: cellularity, plasmablastic cells, background necrosis (BN), single-cell necrosis (SCN), lymphoglandular bodies (LGB), tingible-body macrophages (TBM), 3-dimensional clusters/sheets, and cytoplasmic vacuoles.

The patients included 3 women and 2 men with an age range of 40 to 57 years. Two patients had the acquired immunodeficiency syndrome and 3 had second non-PBL related malignancies including endometrial carcinoma, lung adenocarcinoma, and small lymphocytic lymphoma. The most common cytologic features were hypercellularity (80%), plasmablastic cells (73%), SCN (73%), BN (87%), and LGB (66%). TBMs (33%) and clusters/sheets (47%) were the least common features.

Although no 1 cytologic feature is diagnostic of PBL, a constellation of findings should raise suspicion. These include hypercellular specimens with abundant plasmablastic cells, LGB, SCN, and BN. However, although these findings may suggest PBL, a definitive diagnosis requires adjunctive studies including immunohistochemistry and flow cytometry. As with any lymphocyte-rich aspirate, additional material should be collected for these studies. Over-reliance on adjuvant studies is discouraged because the PBL immunophenotype is not considered standard.