B cell neoplasms with plasmablastic differentiation: a clinicopathological analysis

Purpose To study the clinical and histopathologic features,diagnosis and differential diagnosis of B cell neoplasms with plasmablastic differentiation.Methods Three rare cases of B cell neoplasms with plasmablastic differentiation(plasmablastic lymphoma,PBL,plasmablastic plasma cell myeloma,PPCM,anaplastic plasma cell myeloma,APCM) were studied by microscopy,immunohistochemistry and in situ hybridization,with review of related literature.Results Plasmablasts were seen in PBL,PPCM and APCM.The cases were all positive for CD38,CD138 and MUM1,but negative for CD20 and PAX5 and with high index of Ki-67.PBL patient had a history of immunodeficiency,PPCM and APCM patients had multiple lytic bone lesions and high level of serum immunoglobulin.Immunoblast-like cells were present in both PBL and APCM cases.EBER were negative in the three cases.The case of PPCM was progressed from usual type of plasma cell myeloma.Conclusions PBL,PPCM and APCM all have the features of plasmablasts,whose histology and immunophenotype are similar,but differential diagnosis is difficult.The definite diagnosis of PBL and plasma cell myeloma is important for clinical therapy,and close combination with clinical features is necessary for pathological diagnosis.Plasma cell myeloma can progress into high grade neoplasm.