Pleural Fluid Cytology of the Polymorphous Variant of EBV-Positive Diffuse Large B-Cell Lymphoma: First Report and Distinction from a Reactive Process

EBV-positive diffuse large B-cell lymphoma of the elderly is a newly described aggressive lymphoma predominantly affecting patients >50 years of age. Patients may present with nodal and/or extranodal involvement. The lung is one of the more common extranodal sites. The incidence of pleural fluid involvement is less well described. In one study by Oyama et al., pleural effusions were noted in nine percent of cases. Identification of pleural fluid involvement could be important as it may carry prognostic importance in staging (it typically occurs more often in cases with widespread disease), and it could be a relatively easy means of establishing a diagnosis in newly presenting cases. We report the first description of the pleural fluid cytology in a case of EBV-positive diffuse large B-cell lymphoma of the elderly.