2021 Volume 70 Issue 1 Pages 144-149
Background: Plasmablastic lymphoma (PBL) is a rare malignant lymphoma occurring in immunocompromised patients caused by human immunodeficiency virus (HIV) infection and in elderly persons. We report a case of PBL diagnosed by immunohistochemical examination of a cytology cell block of pericardial fluid. Case: An elderly male patient in his 80s complained of backache on the left side. Computed tomography (CT) examination revealed bilateral pleural effusion and a large amount of pericardial fluid. Pericardial cavity puncture was performed under echo guidance, followed by cytodiagnosis of the pericardial fluid. Pericardial fluid cytology showed a large number of atypical cells of medium to large size with large irregular nuclei and prominent nucleoli. PBL or myeloma was suspected rather than primary effusion lymphoma after the immunohistochemical examination of the cell block. The pleural effusion cytodiagnosis was negative for the atypical cells. The bone marrow aspiration performed for excluding myeloma did not reveal any significant findings. Although gallium scintigraphy and positron emission tomography-CT were performed, the local existence of the tumor was not confirmed. No M protein was detected by serum immunoelectrophoresis, nor was the Bence Jones protein detected by urine immunoelectrophoresis. Therefore, there was no definitive diagnosis, but PBL was highly suspected. Conclusion: We encountered one case of PBL diagnosed by pericardial fluid analysis. Histological examination could not be performed because there were no tumor masses; hence, cytodiagnosis and immunohistochemical examination of the cell block were effective for the diagnosis. Thus, we reconfirmed the importance of making a cell block specimen with body-cavity fluid cytodiagnosis.
