Nodal Marginal Zone Lymphoma Flashcards
What is the definition of Nodal Marginal Zone Lymphoma ?
- primary nodal B cell neoplasm
- morphologically it resembles lympho nodes involved by marginal zone lymphoma of extranodal sites or the spleen
- BUT there can be no evidence of extranodal disease
What is the epidemiology of Nodal Marginal
Zone Lymphoma ?
- rare lymphoma (1.5-1.8%)
- usually seen in people ~60 years of age
- M = F ratio
IMP: this lymphoma can be seen in kids, but it is then classified as Pediatric Nodal Marginal Zone Lymphoma
IMP: there has been a noted increased incidence in women with autoimmune disorders.
What are the sites of involvement of
Nodal Marginal Zone Lymphoma?
- peripheral lymph nodes
- sometimes can also involve the bone marrow and peripheral blood
IMP: cannot have evidence of extranodal disease, otherwise is most likely lymph node involvement by an extranodal MALT lymphoma.
What are the clinical features of Nodal
Marginal Zone Lymphoma ?
- usually patients are asymptomatic and present with localized or generalized peripheral lymphadenopathy
- head and neck lymph nodes are most frequently involved
- B symptoms are present in up to 20% of patients
- exclude an extranodal MALT
- MALT associated with Hashimoto or Sjogrens often disseminates to the lymph nodes
What are the microscopic findings for a
Nodal Marginal Zone Lymphoma ?
- small lymphocytes that surround reactive follicles and expand into the interfollicular zones
- follicular colonization can be seen
- IF there is a diffuse pattern, residual follicles can be highlighted by IHC
- Variable infiltrate of marginal zone B lymphocytes (centrocyte like), scattered plasma cells and transformed B cells (immunoblasts/centroblasts)
- IMP: cases with predominantly monocytoid B cells are uncommon
What is the differential diagnosis when there
is extensive plasmacytic differentiation of the
nodal marginal zone lymphoma ?
- Lymphoplasmacytic lymphoma
- Nodal plasmacytoma
IMP: the presence of remnants of FDC meshworks favors NMZL because it likely represents colonization of the follicles.
What does the presence of increased large
cells mean?
- Does not mean anything necessarily, may have >20% large cells but they should still be scattered amongst the other cells
- They may be more common in the colonized germinal centers
IMP: a composite marginal zone lymphoma and Hodgkin lymphoma have been reported.
What is the pattern of bone marrow involvement ?
What is the immunophenotype of Nodal
Marginal Zone Lymphoma ?
- pan B cell markers
- CD43 co-expression in 20-75% of cases
- CD23 is usually negative
- but it can be expressed in as many as 30% of cases
- CD5 may be seen in up to 20% of cases
- tend to have more disseminated disease if positive but it does not affect their prognosis
- Bcl2 positive in most cases
- Cyclin D1
- Negative
- Germinal center markers (CD10, Bcl6, HGAL, and LMO2)
- Negative but rare reports of positivity
- IMP: co-expression of more than one GC marker in the interfollicular areas favors a Follicular lymphoma
How can IgD IHC help differentiate nodal MZL
from other lymphomas?
- IgD is usually negative in nodal MZL
- IgD is positive in other lymphomas that can mimic MZL immunophenotypically
How can MNDA and IRTA1 IHC
help differentiate follicular lymphoma from
nodal Marginal zone lymphoma ?
- MNDA and IRTA1 are positive in 75% of cases of nodal marginal zone but are usually negative in follicular lymphoma
What is the normal postulated counterpart
of nodal marginal zone lymphoma ?
- post-germinal centre marginal zone B cell
What immunoglobulin genes are frequent clonally
rearranged in nodal MZL ?
- predominance of mutated IGHV3 and IGHV4 family members
- IGHV4-34 are the most common
- In cases that are associated with hepatitis C virus infection, IGHV1-69 are clonally rearranged
What similar chromosomal abnormalities does
nodal MZL share with splenic and extranodal MZL ?
- Gains of chromosomes 3 and 18
- Loss of 6q23-24
IMP: no deletions of 7q31 or any recurrent translocations are noted.
What has gene expression profiling identified in
nodal MZL ?
- increased expression of NF-kappaB related genes
- MYD88 L265P mutation is usually absent but can occasionally be detected.