B cell neoplasms: CLL, Mantle cell, & Follicular Flashcards
What can be the clinical
presentation of B cell neoplasms ?
- lymphadenopathy
- peripheral blood lymphocytosis
- cytopenia
- M protein
- B symptoms
- fever, night sweats, and loss of >10% body weight
What are the common sites for
extranodal B cell lymphomas?
- GI tract
- stomach is most common
- Skin
- Bone
- CNS
What B cell neoplasms can present
as leukemia ?
- CLL
- Prolymphocytic leukemia
- Hairy cell leukemia
- B-ALL
B cell neoplasms have various tendencies for marrow involvement. Which neoplasms
involve the marrow in a paratrabecular pattern?
- Follicular lymphoma
- 1/3 grade discordant with lymph node and bone marrow, can be prognostically important
- sometimes Marginal zone lymphoma but not frequently
Which B cell neoplasms involve the marrow in a nodular pattern ?
- Mantle cell
- 20% involve the marrow
- Marginal zone
- 5% involve marrow
- 80% involve the peripheral blood
Which lymphoma involves the bone marrow in
an interstitial pattern?
- lymphoplasmacytic lymphoma
- 10% involvement of bone marrow
- 10% involve peripheral blood
Which lymphomas can involve the bone marrow
in a diffuse pattern ?
- DLBCL
- 15% involve the bone marrow
- Burkitt lymphoma
- 5% involve marrow
What are some of the risk factors
for developing B cell neoplasms?
- immunodeficiency
- autoimmunity
What is the most common B cell
leukemia in adults in the Western hemisphere ?
- CLL/SLL
- CLL demonstrates the strongest genetic influence
- familial clustering in 5% of cases
- 5X increased risk in first degree relatives of affected individuals
- incidence increases with age, median age of 65 years
- CLL demonstrates the strongest genetic influence
What is the clinical presentation of CLL/SLL ?
- generalized lymphadenopathy, splenomegaly, peripheral blood lymphocytosis
- KNOW- autoimmunity and immunodeficiency are common
- cytopenias
- caused by autoimmunity rather than by marrow replacement
- positive DAT
- full blown autoimmune hemolytic anemia
- M protein- occasional
What is the morphology of SLL ?
- diffuse nodal effacement by small, mature appearing lymphocytes
- rounded nuclear contours
- coarse chromatin
- scant cytoplasm
- Proliferation centers (pseudofollicles)
- pale nodules
- filled with prolymphocytes and paraimmunoblasts
What is thought to be a histologic subtype
with aggressive clinical behavior
for SLL?
- when the proliferation centers are expanded and highly active
- Ki67 > 40%
What is the morphology of
CLL ?
- lymphocytosis composed of small, mature appearing lymphocytes with scant cytoplasm
- coarsely clumped chromatin
- smudge cells
- this is an EDTA artifact
- not seen on Heparin smears
- can reduce by replacing albumin
What is the definition of
CLL by the WHO ?
- absolute lymphocyte count > 5 x 10 ^9/L
- or 5,000/uL
- can be the sole criterion
- but if you have tissue infiltration by CLL then just call CLL
What is the definition of
monoclonal B cell lymphocytosis (MBL) ?
- monoclonal B cell population
- immunophenotypically identical to CLL
- BUT
- no tissue involvement
- < 5 x 10 ^9/L (5,000/uL)
- MBL can be found in 3.5% of the population normally when over 40 years old
What is the morphology of
Prolymphocytes in CLL ?
- prolymphocytes are characterized by an increased volume of cytoplasm, open chromatin, and central prominent nucleoli
- should comprise 10% or less of the population
What is the definition of CLL
with increased prolymphocytes ?
- 11-55% prolymphocytes in addition to the normal CLL population
Note: prolymphocyte counts of >15 x 10^9/L appear to have poor clinical outcome
What is the definition of prolymphocytic leukemia?
- > 55% prolymphocytes
- rarely evolves from CLL
- often is de novo
What is the pattern of involvement
of CLL in the bone marrow ?
- nodular
- good prognosis
- diffuse
- poor prognosis
What is the immunophenotype of
CLL/SLL ?
- Positive
- CD19, CD20 (dim), CD22
- CD5, CD23
- surface Ig (dim)
- CD43, CD79a
- CD11c (dim and variable)
- LEF1
- expression is highly specific for CLL/SLL
- Negative :
- FMC7, CD10, BCL6, and BCL1
In CLL, what does expression of
CD38 and ZAP70 imply?
- implies an unmutated IgVH status and an unfavorable diagnosis
What are the common cytogenetic
findings in in CLL/SLL ?
- 30% of cases have complex abnormalities
- deletion of 13q14 (50%) **
- trisomy 12 (20%)
- del (11q)
- del(14q)
- del(17p)
Richter Syndrome/transformation to a large B cell lymphoma occurs in 3-15% of cases
What is the single most important
prognostic factor in CLL/SLL ?
- mutation status of the IgH variable region
- CLL with unmutated IgVH resembles pre-GCB cells and are likely to have poor prognosis
What are other indicators of
worsened survival in CLL?
- B symptoms
- peripheral lymphocyte doubling time less than 1 year
- higher initial lymphocyte count (esp >30,000)
What is correlated with ZAP70 or CD38 +
in CLL ?
- expression correlates with atypical morphology
- unmutated IgVH and worsened prognosis
Note: for designation of CD38+, over 30% of neoplastic cells should express CD38
How do the cytogenetics of CLL affect
the prognosis of patients ?
-
11q and 17p deletions
- shortest survival with these findings
- isolated del 13q14
- stable course
- isolated trisomy 12
- impact unclear
- generally considered adverse
-
t(14;19)
- translocation associated with bcl3 expression
- atypical morphology, trisomy 12
- aggressive disease
How is CLL treated?
- watchful waiting
- Fludarabine: purine analog
- with chemo and rituximab, or alone
- Ibrutanib
- used in CLL with del17p
- also in relapsed refractory cases
What are some general facts about
Mantle Cell Lymphoma ?
- aggressive disease with median survival of 3-4 yrs
- occurs in adults, usually men
- often occurs in Waldeyer’s ring and the GI tract
- Lymphomatoid polyposis
- endoscopic involvement in 60% of patients
- Lymphomatoid polyposis
What is the morphology of Mantle Cell Lymphoma?
- diffuse or vaguely nodular effacement of the lymph node architecture
- small to medium sized lymphocytes
- irregular contours
- small subtle nucleolus
- look like boulders
- Germinal centers without mantle zones
- pink histiocytes
- hyalinized blood vessels
What are the variants of Mantle Cell Lymphoma ?
- blastoid
- pleomorphic
- small cell
- marginal zone like
- peripheralized (nodal MCL with circulating cells)
- leukemic nonnodal mantle cell lymphoma
What is the morphology of a blastoid and pleomorphic variants
of MCL ?
* Both are considred more aggressive variants
Blastoid Variant
- large cells with open chromatin
- high mitotic rate
Pleomorphic Variant
- mixture of cell sizes
- many large cells with nucleoli
What is the main differential for
MCL ?
- Lymphoblastic leukemia/lymphoma
- will lack BCL1 and CD5
- will express CD99 and Tdt
How can mantle cell neoplasia in situ be
identified vs. reactive follicles ?
- cyclin D1 expression is seen in the mantle zones
What is the characteristic immunophenotype for
Mantle Cell Lymphoma ?
- Positive
- CD19, CD20 (bright), CD22
- FMC7, CD5, CD43
- surface Ig (bright)
- bcl 1 (cyclin D1)
- more likely to be lambda restricted compared to kappa
- Negative
- CD23
- CD11c
- CD10
What is the utility of SOX11 in Mantle Cell Lymphoma ?
- Sox11 is a transcription factor
- increased sensitivity and specificity
- often used in cyclin-D1 negative cases
What are the cytogenetics of Mantle cell lymphoma?
- t(11;14)
- results in a translocation of IgH (14q32) gene of the CCND1 (11q13)
- results in cyclin D1 amplification identified by FISH
What are the key prognostic things for Mantle cell lymphoma ?
- single most important factor is proliferative activity
- mitosis > 50 per mm^2 - correlate with worse prognosis
- Ki67 > 30% correlates with adverse prognosis
Note: blastoid and plemorphic morpholgy are thought to be adverese
What is the common clinical presentation of
Follicular lymphoma ?
- uncommon to be found in extranodal sites
- isolated lymphadenopathy without constitutional symptoms
- bone marrow is involved in ~30% of cases
- paratrabecular growth
What is the morphology of Follicular lymphoma ?
- nodular lymphoid proliferation that typically overruns the lymph node capsule (uniform in size cells)
- back to back fused follicles with attenuated mantles
- loss of polarity of GC
- absence of tingible body macrophages
- diminished mitosis
- Note: see diffuse areas and sclerosis in mesenteric or retroperitoneal LN
What are the 2 cell types present in
Follicular Lymphoma ?
- 2 cells types are present in varying proportions
- centrocytes
- large noncleaved cells (centroblasts)
How is grading of Follicular Lymphoma performed
and what is considered Grade 1 ?
- based on the proportion of large non-cleaved cells (centroblasts)
- evaluate a 40x field of 10 randomly selected neoplastic follicles
- do not specifically pick the worse areas
- Grade 1:
- 0-5/40x
Note: Grade 1 and 2 are assigned as low-grade
How are Grade 2 and 3 assigned to a Follicular Lymphoma ?
- Grade 2:
- 6-15/ 40x HPF
- Grade 3:
- 3A: >15 /40x HPF
- 3B: no centrocytes are visible in 40x field
What is considered diffuse growthin in Follicular Lymphoma ?
- an area where follicular architecture is lost
- lacks FDC by CD21 or CD23 IHC
- Grade 3 Diffuse areas have a diagnosis of DLBCL
- background FL also noted
What is the morphology of Follicular Lymphoma cells
in peripheral blood ?
- buttock cell –> very indented nucleus
What is the definition of in situ Follicular Neoplasia?
- germinal center looks architecturally reactive
- cytological features of follicular lymphoma
- monomorphous, centrocyte rich
What is the clinical presentation and important
characteristics of Primary cutaneous FL ?
- low rate of LN lymph node involvement and an excellent overall prognosis
- IHC
- variable CD10, lack of bcl2 expression
- bcl6 is positive
- IF FL in skin expresses
- CD10 and or BCL2
- suspect systemic involvement by FL
What is characteristic of the floral variant
of Follicular Lymphoma ?
- mantle zone B cells penetrate into the neoplastic follicles
- create irregular shapes
- can highlight the morphology using FDC markers- CD21
- often a Grade 3 lymphoma
What is characteristic of the duodenal type
of Follicular Lymphoma ?
- rare
- presents as multiple polyps in the 2nd portion of the duodenum (most common site)
- low rate of lymph node dissemination
- excellent prognosis if surgically removed even
What is important to know about testicular FL ?
- High grade follicular lymphoma
- especially in children
- lacks the bcl2 translocation
- Good prognosis
What is important to know about
Pediatric Follicular lymphoma ?
- often presents with localized cervical lymphadenopathy
- lacks bcl2 expression
- lacks bcl2 rearrangement
- usually Grade 3
- Excellent prognosis
What is the pattern of
bone marrow involvement by
Follicular Lymphoma ?
- focal paratrabecular aggregates
- this pattern is only seen with FL and occasionally TCRBCL
- Note: sometimes mantle cell can show this pattern
Why is it important to evaluate the bone marrow
in Follicular Lymphoma ?
- if there is a high grade lymphoma elsewhere, but lower grade in the bone marrow it imparts a better prognosis
- worse prognosis if both are high grade
What is the immunophenotype of
Follicular Lymphoma ?
- Positive:
- CD19, CD20, CD22
- FMC7, CD10, surface Ig bright
- bcl6 and bcl2
Note: CD10 and bcl2 can be lost in higher grade
- Negative
- CD5, CD43, CD11c
- variable CD23
Note: CD21 and CD23 highlight FDCs, without staining supports a diffuse pattern
What is the characteristic
cytogenetic alteration of
Follicular Lymphoma ?
- t(14;18)
- results in a BCL2 rearrangement with IGH
- bcl2 protein overexpression
What is the prognosis
of Follicular Lymphoma ?
- median survival of 8-10 years
- eventually progresses/transforms to high grade FL or DLBCL
What factors have been associated with
progression in Follicular Lymphoma ?
- age
- stage
- bone marrow involvement
- B symptoms
- performance status
- serum LDH levels
- anemia
What is the clinical presentation of
Large B cell lymphoma with
IRF4 (MUM1) rearrangement ?
- usually seen in children and young adults
- involves Waldeyer’s ring
- also seen in head and neck lymph nodes
- Favorable prognosis
What is the morphology and IHC
profile of Large B cell Lymphoma
with IRF4 (MUM1) rearrangement ?
- diffuse
- follicular and diffuse
- or entirely follicular
- usually Grade 3
Immunohistochemistry
- (+) : MUM1 and bcl6
- CD10 (+) in 65% of cases
What is the genetic alteration
of Large B cell Lymphoma with
IRF4 rearrangment ?
- t(6;14)
- IGH-BCL2
- usually IRF4 gene rearranged with BCL6