B Cell Lymphomas Part I (LPL and Large Cells) Flashcards
What sites must be involved by
Lymphoplasmacytic lymphoma
to fit criteria?
- must involve the bone marrow
- can be seen in LN, blood and extranodal sites
- original cell:
- Memory B cell
What spectrum of morphology cacn be
observed in Waldenstrom Macroglobulinemia
(LPL)?
- can have small lymphoid cells
- lymphoplasmacytoid cells
- plasma cells
- Dutcher bodies may be seen
- Lymph node architecture
- can be preserved with cells in sinuses
- or effaced
- PAS + material in sinuses, dutcher bodies
IMP: mast cell infiltrates accompany LPL in bone marrow, also amyloid
What are some clinical associations
of Lymphoplasmacytic lymphoma?
- Hepatitis C
- Cryoglobulinemia
IMP: these will respond to antiviral therapy
What is Waldenstroms Macroglobulinemia?
- lymphoplasmacytic lymphoma with an IgM monoclonal gammopathy
- marrow is also involved
What is the immunophenotype of
Lymphoplasmacytic lymphoma?
- Positive:
- CD19, CD20, CD38
- surface Ig bright
- cytoplasmic Ig in plasma cells
- Negative (or sometimes dim)
- CD5, CD23
- CD43 and CD10
What are the genetics of
Lymphoplasmacytic Lymphoma?
- MYD88 L265P gene mutations in >90% of LPL
- CXCR4 mutations are associated with poor prognosis and resistance to therapy
What is heavy chain disease and what is the most
common cause of it?
- rare, LPD that only forms immunoglobulin heavy chains
- Most common:
- alpha H chain disease
- also known as Mediterranean lymphoma
- stimulated by C. jejuni
- associated with immunoproliferative small intestine disease
What is Franklin H chain disease?
- form of heavy chain disease
- gamma heavy chain
- history of rheumatoid arthritis
- in 1/3 of patients
What is the most frequent clinical presentation
of DLBCL, NOS?
- rapidly enlarging nodal or extranodal mass (often in the GI tract)
- usually localized at presentation
- bone marrow involvement seen in 10% of patients
- 1/3 of patients have B symptoms
- 1/3 have elevated LDH at presentation
What is the frequent morphology seen in
DLBCL, NOS?
- diffuse proliferation of large lymphoid cells
- nuclei are at least as large as that of a macrophage or twice the size of a lymphocyte
- morphology can be:
- centroblastic
- immunoblastic
- anaplastic
What is the typical immunohistochemistry
of DLBCL, NOS?
- Positive:
- CD19, CD20, CD22, and CD45
- usually BCL2
- variable: CD10, CD5, and BCL6
Note: CD5 + DLBCL distinguished from blastoid MCL
- lack of BCL1 expression or CCND1
In DLBCL what does expression
of CD10 and BCL6 correlate with?
- germinal center phenotype
- more favorable prognosis
Note: expression of MUM1 in the absence of CD10 indicates an activated B cell type (worse prognosis)
What morphological features point towards
GCB vs. ABC?
- GCB:
- more centroblastic morphology
- BCL2 t(14;18) more common
- ABC:
- more immunoblastic morphology
- BCL6 t(3;x)
What is the definition of
Primary DLBCL of the CNS?
- specifically excludes dural lymphoma, intravascular lymphoma, secondary involvement by systemic lymphoma, and lymphoma associated with immunodeficiency
- median age is 60
What is the clinical presentation of
a Primary DLBCL of the CNS?
- supratentorial mass within the frontal, temporal or parietal lobes
- solitary or multifocal lesions with radiographic features that mimic glioblastoma
- tendency to spread along the white matter tracts
- cross the midline
- may present or recur as intraocular lymphoma
