title: A unique case of B cell lymphoma relapsing as CD4/CD56 blastic neoplasm.
abstract: A patient with history of B cell lymphoma treated with rituximab-based chemotherapy relapsed with a blastic CD4+/CD56+ neoplasm that was negative for CD20, CD79a and CD3. The relapse morphology and immunophenotyping were unusual and plasmacytoid dendritic cell (PDC) tumor enters the differential diagnosis. However, expressions of Oct-2 and CD10 in the relapse tumor were both more compatible with B cell than PDC lineage. Molecular investigations showed clonal rearrangements for both immunoglobulin heavy chain (IgH) and T cell receptor (TCR) gamma chain gene by polymerase chain reaction (PCR). Furthermore, a clonal relationship with the original B cell lymphoma was demonstrated for all PCR products. Our case illustrated the potential pitfalls and ambiguity of lineage classification based on morphology and immunophenotyping alone, especially for rare and poorly defined entities.
authors.affiliation: Department of Medicine, Queen Mary Hospital, Pokfulam, Hong Kong. auwing@hotmail.com
authors.forename: Wing Y
authors.initials: WY
authors.lastname: Au
authors.forename: Kai Y
authors.initials: KY
authors.lastname: Wong
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Wan
authors.forename: Jason C
authors.initials: JC
authors.lastname: So
authors.forename: Gopesh
authors.initials: G
authors.lastname: Srivastava
authors.forename: Raymond
authors.initials: R
authors.lastname: Liang
mesh_terms: D000369:Aged, 80 and over; D018951:Antigens, CD20 / Q000032:analysis; D001483:Base Sequence; D015704:CD4 Antigens / Q000032:analysis*; D019002:CD56 Antigen / Q000032:analysis*; D003713:Dendritic Cells / Q000378:metabolism / Q000473:pathology; D003937:Diagnosis, Differential; D005434:Flow Cytometry; D015321:Gene Rearrangement; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D016130:Immunophenotyping; D007621:Karyotyping; D016393:Lymphoma, B-Cell / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008969:Molecular Sequence Data; D009364:Neoplasm Recurrence, Local; D014411:Neoplastic Stem Cells / Q000378:metabolism / Q000473:pathology; D050813:Octamer Transcription Factor-2 / Q000032:analysis; D016133:Polymerase Chain Reaction; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid
chemical_list: D018951:Antigens, CD20; D015704:CD4 Antigens; D019002:CD56 Antigen; D007143:Immunoglobulin Heavy Chains; D050813:Octamer Transcription Factor-2; D016692:Receptors, Antigen, T-Cell, gamma-delta