Small B Cell NHLs Flashcards
what are small B cell NHLs derived from?
mature B cells
is bone marrow involvement common in small B cell NHLs?
yes. lots of stage 4 disease (as well as liver/spleen involvement)
immunophenotypic profile for follicular lymphoma
CD19/20+ (mature B cell)
CD5- (not T cell)
kappa/lambda restricted
CD10+, BCL6+, BCL2+ (germinal center origin, but cells don’t apoptose)
immunophenotypic profile for CLL/SLL
CD19/20+ (mature B cell)
CD5+ (aberrant T cell marker)
kappa/lambda restricted
CD10-, BCL6-, BCL2+ (not from germinal center)
immunophenotypic profile for marginal zone lymphoma (MALT)
CD19/20+ (mature B cell)
CD5- (not T cell)
light chain restriction
CD10-, BCL6-, BCL2+ (not germinal center origin)
** no distinct immunophenotypic marker***
what is the most common NHL?
follicular lymphoma
what age group does follicular lymphoma affect?
middle age and older
morphology of follicular lymphoma
nodular neoplasm within lymph node. loss of mantle, polarity, tingible macrophages. complete loss of normal features. Contains centroblast & centrocytes.
growth of follicular lymphoma
indolent
clinical manifestation of follicular lymphoma
generalized lymphadenopathy, typically caught at stage 4 (disseminated) due to slow growth. spleen/liver involvement common with miliary lesions and painless splenomegaly. extra nodal involvement is uncommon.
prognosis of follicular lymphoma
incurable due to indolent growth (therapies target cell division). 7-9 year survival
current therapy for follicular lymphoma
observation, symptomatic relief, Rituxan, multiagent regiments (CHOP)
more severe follicular lymphoma
can transform into diffuse large b cell lymphoma. can occur after treatment and cuts survival to <1yr
derivation of follicular lymphoma
germinal center B cell
centrocytes
small cleaved, low grade germinal center b cells that can disseminate through the blood
centroblasts
large, transformed noncleaved germinal center B cells.
how to grade follicular lymphomas
- Cytology: centroblast count
- Extent of nodularity
(higher grades=higher centroblasts, diffuse nodules=more aggressive)
bone marrow pattern in stage 4 follicular lymphoma
paratrabecular aggregates
follicular lymphoma translocation
t(14;18). IgH-Bcl2=constitutive Bcl2 activity=no apoptosis
Ki67 in follicular lymphoma
low. cells aren’t proliferating because they aren’t dying. Just accumulate instead.
CLL/SLL derivation
unclear. either 1. mature B cells that just left marrow, haven’t encountered antigen, no TdT/CD34, with light chains or 2. B cells that encountered antigen in follicle and are chilling in the margin
CLL/SLL stands for…
Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (circulating cells and solid masses)
epidemiology of CLL/SLL
affects 60+ and males more than females. most common adult leukemia
clinical features of CLL/SLL
usually asymptomatic, generalized lymphadenopathy, always stage 4, spleen&liver involvement, peripheral blood involvement (unlike FL), immune dysregulation (AIHA or thrombocytopenia) caused by normal B cells
CLL/SLL prognosis
variable survival 4-6 years, easily transforms to prolymphocytic leukemia or undergoes Richter’s Transformation (both <1yr survival and resistant to treatment)
Richter’s Transformation
transformation of CLL/SLL to diffuse large B cell lymphoma
CLL/SLL morphology
diffuse sheet of small resting lymphocytes in lymph node with proliferation centers of larger transformed cells with more cytoplasm (pro lymphocytes or paraimmunoblasts). No follicle structure, effacement of architecture
peripheral blood smear of CLL/SLL
lymphocytosis, smudge cells (disrupted white cells), spherocytes (autoimmune attack), nucleated RBCs, increased reticulocytes (polychromasia)
CLL/SLL bone marrow involvement
nodular aggregates (or diffuse spread) in marrow away from trabecular in area of interstitium
naive form of CLL/SLL
contains rearranged but unmutated Ig, pre-germinal center, Zap70+, aggressive form of the disease
post germinal center form of CLL/SLL
contains rearranged and somatically hyper mutated Ig genes, has traversed GC. Zap70-, Indolent
Marginal Zone Lymphoma origin
comes from ill defined area outside germinal center where B cells go after encountering antigen and either become memory or plasma B cells.
three separate marginal zone lymphoma diseases
Nodal, Muscosal/Extranodal (MALT), Splenic
MALT stands for…
extranodal marginal zone lymphoma of mucosa associated lymphoid tissue
Cause of MALT
chronic inflammatory lesions (helicobacter, campylobacter, ect)
MALT prognosis
indolent, but still can transform to diffuse large B cell lymphoma
sites of MALT
Stomach, Small bowel, skin, orbit, Lung, Parotid, thryoid
MALT morphology
abnormal germinal centers with expanded margins, and effacement of underlying architecture. small mature lymphocytes beyond margin, monocytoid b cells in margin, ample plasma cells
consequence of increased plasma cells in MALT
can secrete a low level of Ig into serum and urine (paraprotein)
main mechanism of MALT lymphomas
inhibit apoptosis/promote cell growth via NF-kB activation
treatment of MALT
can treat underlying infections up to a certain point and neoplasm will regress. eventually cellular change will be independent of inflammatory stimulus and chemotherapy is required
