Surgical Pathology Criteria–

Plasmablastic Lymphoma

Differential Diagnosis

 

Plasmablastic Lymphoma Immunoblastic DLBCL
Typically oral cavity mass in HIV+ patient Wide variety of presentations, including HIV
LCA negative or minimal + LCA >90%
CD20 minimal to negative, CD79a positive Both CD20 and CD79a >90%
Ki67 >95% Ki67 moderately high, variable
EBV in situ 50% EBV in situ rare in de novo cases; frequent in immunodeficiency cases
CD138 positive CD138 negative
Amphophilic cytoplasm and pleomorphic nuclei with prominent nucleoli may cause difficulty with distinction of plasmablastic lymphoma from immunoblastic large B cell lymphoma

 

Plasmablastic Lymphoma Primary Effusion Lymphoma
Not body cavity based (frequently oral cavity) Involves body cavity
CD45RB weak to negative CD45RB positive
HHV8 only if associated with Castleman disease HHV8 positive
Both are usually associated with HIV and most are EBV+ and CD20 negative

 

Both entities share cytologic features and may also be CD20 and CD45RB negative or minimally reactive

Plasmablastic Lymphoma ALK Positive DLBCL
Typically oral cavity mass in HIV+ patient Wide variety of presentations
ALK negative ALK positive
CD79a positive CD79a negative
CD138 positive CD138 negative

 

Plasmablastic Lymphoma Anaplastic (Plasmablastic) Plasmacytoma/Myeloma
Plasmablastic morphology Subset plasmablastic
Often HIV+ or otherwise immunosuppressed Usually not immunosuppressed
Often in oral cavity or mucosal areas of head Extraosseous sites overlap
~60% EBV+ usually EBV negative
Plasmacytoma and plasmablastic lymphoma have the same immunophenotype, other than EBV and are generally separated based on clinical grounds

Plasmablastic Lymphoma KSHV-associated Germinotropic Lymphoproliferative Disorder
Typically oral cavity Localized lymphadenopathy
Immunosupressed patient Immunocompetent patient
Sheets of plasmablasts Plasmablasts involve germinal centers
Some cases associated with multicentric Castleman disease (MCD) No Castleman features in follicles
EBV 50% positive EBV positve
Plasmablasts are the lesional cells in both disorders and both may be HHV8 positive

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