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plasmablastic lymphoma

Wednesday 16 November 2005

diffuse large B-cell lymphoma of plasmablastic type, plasmablastic DLBCL,

Definition: Plasmablastic lymphoma (PBL) is an aggressive lymphoma characterized by a terminally differentiated B-cell phenotype that usually occurs in the immunocompromised or elderly patients.

Images

- Plasmablastic lymphoma with opartial CD3 expression

PBL are genetically characterized by frequent IG/MYC translocations and gains in multiple chromosomal loci. The oncogenic activation of MYC in these lymphomas may be an important pathogenetic element associated with EBV infection. (20962620)

PBL is a rare neoplasm which is a high grade lymphoid malignancy first reported in the oral cavity of individuals infected with human immunodeficiency virus (HIV). It is now known to occur in patients which immune suppression from other etiologies, and in sites other than the oral cavity. The majority of cases are associated with EBV.

The 2008 WHO classification of tumors of hematopoietic and lymphoid tissues states that PBL is a diffuse proliferation of large neoplastic cells resembling B immunoblasts, but that the tumor cells have an immunophenotype of plasma cells. Other authors have described these cells as “plasmablasts.”

These neoplasms are aggressive and often originate in the oral cavity mucosa and gingiva, but they may involve the adjacent bone. Often these cases are confined to the oral cavity at presentation. In the head and neck, in addition to the oral cavity PBL may originate in the sinonasal tract.

PBL may be derived from post-germinal center B cells or naïve B cells undergoing preterminal differentiation (short lived plasma blasts); it is unclear if these cells have undergone germinal center transit.

PBL is comprised of cells showing large cells with round to oval nuclei which may be eccentric. A central prominent single nucleoli is usually present. The cytoplasm is abundant with a paranuclear clear zone or hof.

Plasmablasts express CD138 and IRF4 (MUM1) but do not express CD20 or PAX5.

CD56 is negative in the majority of cases helping to exclude plasmacytoma which are often CD56 positive.

EBV staining with in situ hybridization for EBER is positivity in the lesional cells. An high proliferation rate is seen by Ki67 staining.

The term PBL should be restricted to cases with this histology and phenotype and not confused with plasma cell myeloma showing immature features.

Synopsis

- blastic appearing cells with plasmacytoid cytoplasm and central nuclei;
- mitoses are numerous.
- Ki67 is near or at 100%.
- CD138 is strongly positive.
- EBER stains many of the cells in a nuclear pattern by in situ hybridization.
- These cells were also negative for CD20, CD79a and CD56.

Risk factors

- EBV infection
- HIV infection

Variants

- pleomorphic lymphomas

Cytogenetics

- t(2;5)(p23;q35) (14576483)
- MYC rearrangements (20348882, 20962620)

See also

- B-cell tumors
- plasma cell dyscrasias

Reviews

- http://www.semdiagpath.com/article/S0740-2570(14)00108-7/fulltext

References

- Plasmablastic lymphoma with MYC translocation: evidence for a common pathway in the generation of plasmablastic features. Taddesse-Heath L, Meloni-Ehrig A, Scheerle J, Kelly JC, Jaffe ES. Mod Pathol. 2010 Jul;23(7):991-9. PMID: 20348882 (Free)

- IG/MYC rearrangements are the main cytogenetic alteration in plasmablastic lymphomas. Valera A, Balagué O, Colomo L, Martínez A, Delabie J, Taddesse-Heath L, Jaffe ES, Campo E. Am J Surg Pathol. 2010 Nov;34(11):1686-94. PMID: 20962620

- Adam P, Katzenberger T, Seeberger H, Gattenlohner S, Wolf J, Steinlein C, Schmid M, Muller-Hermelink HK, Ott G. A case of a diffuse large B-cell lymphoma of plasmablastic type associated with the t(2;5)(p23;q35) chromosome translocation. Am J Surg Pathol. 2003 Nov;27(11):1473-6. PMID: 14576483