2020 Volume 69 Issue 1 Pages 117-124
Background: A plasma cell neoplasm with aberrant expression of T-cell-related antigens is exceedingly rare. In this study, we report a case of dual CD3- and CD4-positive plasma cell neoplasm (PCN). Case: The patient was an 80-year-old woman who was referred to our hospital owing to her general fatigue. There was no palpable mass in the contrast-enhanced CT images; however, laboratory tests revealed high levels of LDH and soluble IL-2R. MRI examination detected an abnormal signal in the cervical spine. Bone marrow biopsy was performed and blastic plasmacytoid dendritic cell neoplasm (BPDCN) was suspected. Four months later, bilateral pleural effusion occurred, and right pleural effusion was obtained for cytological examination. Cytological smears showed mononuclear and multinuclear tumor cells with a perinuclear halo resembling plasma cells. Immunocytochemistry of cell block preparations revealed that the tumor cells were positive for CD3, CD4, CD56, CD138, and kappa light chains. The final diagnosis was PCN. Conclusion: In this patient, although the tumor cells had morphological features of PCN, they were positive for CD3 and CD4. It is important to recognize a plasma cell neoplasm with aberrant expression of T-cell antigens.
