Table 1.

	Description	Presentation	Phenotype
Primary Effusion Lymphoma	Large B cell neoplasm Tumor cells can show immunoblastic, plasmablastic or anaplastic morphology	Serous effusions without detectable tumor masses Can rarely present as solid masses (extracavitary PEL6) Median survival <6 months Often seen in patients with HIV or other immunodeficiency	Always HHV8+ May lack EBV in the elderly Lack pan B-cell markers, but usually MUM-1+ Can show aberrant T cell antigen expression including CD3 Thought to arise from post germinal center B- cells
Multicentric Castleman Disease and associated plasmablastic lymphoproliferative disorders	MCD: Angiofollicular hyperplasia and plasma cell infiltration Large B-cell lymphoma arising in HHV8-associated MCD: monoclonal HHV-8-infected lymphoid cells that resemble plasmablasts, arising in the setting of MCD; as disease progresses the plasmablasts may become scattered in the interfollicular area and coalesce to form clusters or sheets termed microlymphomas	Systemic disease with peripheral or systemic lymphadenopathy, hepatomegaly and/or splenomegaly Often preceded by Kaposi’s sarcoma Predominantly in HIV+ patients	Always HHV-8+ by the 2008 WHO classification46 Generally EBV negative, but EBV/HHV-8 co- infection has been reported with microlymphomas12,13 Plasmablasts express IgM and lambda light chain Lack clonal IgH gene rearrangements Arise from naïve B- cells
Germinotrophic lymphoproliferative disorder	Germinotropic aggregates of plasmablasts	Localized lymphadenopathy Usually seen in HIV- negative patients Indolent course	HHV-8 and EBV+ Lack pan B-cell markers but MUM1+ Polyclonal or oligoclonal IgH Arise from post germinal center B-cells