Marginal Zone Lymphomas

Question 1

What are the 3 distinct subtypes of MZLs?

Answer 1

1) Extranodal MZL of mucosa-associated lymphoid tissue (MALT)
2) Nodal MZL
3) Splenic MZL

Question 2

What are some common infectious pathogens a/w MZLs?

Answer 2

H.Pylori 
Chlamydia psittaci 
Campylobacter jejuni
Borrelia Burgdorferi
Hep C

Question 3

How often is Hep C a/w MZLs?

Answer 3

30%
Esp splenic MZL

HCV has also be reported in about 35% of patients with non-gastric MALTs

Question 4

What is commonly difficult to separate from MZL as a diagnosis?

Any mutations you know of that can help?

Answer 4

Waldenstrom’s Macroglobulinemia/Lymphoplasmacytic lymphoma (WM/LPL)

MYD88 L265P somatic mutation is widely prevalent in WM/LPL patients

IGHV analysis clearly distinguishes splenic MZLs and WM/LPL

• Splenic MZLs were characterized by over representation of IGHV1-2 gene rearrangements with low/intermediate mutation rates
• WM/LPL a/w over-representation of IGHV3-23 rearrangements and high mutation rates.

Question 5

Tell me about the epidemiology of MALT

Answer 5

GI tract most common site of involvement. 50% of MALT lymphomas.

Within GI tract, stomach 80-85%

Other common non-gastric sites include: Orbit, lung, skin

MALT lymphomas tend to be indolent.
Similar long-term outcomes between gastric and non-gastric subtypes.

T(11;18) most common translocation, resulting in formation of chimeric fusion Gene, API2-MALT1
- frequently detected in gastric, pulmonary MALT lymphomas

T(1;14) results in overexpression of BCL10 protein and it occurs in 1-2% of MALT lymphomas.

T(11;18) and BCL10 overexpression a/w locally advanced disease and is less likely to respond to H.Pylori eradication with antibiotic therapy.

T(14;18) results in deregulated expression of MALT1 Gene
- in 15-20% of MALT lymphomas

T(3;14) results in up emulation of FOXP1 Gene, a/w MALT of thyroid, ocular adnexa and sin

Question 6

What is the Lugano staging system for GI lymphomas?

Answer 6

Stage IE = confined to GI tract (can be single or multiple, non contiguous)

Stage IIE = extending into abdomen

Stage IIE + T4N0M0= penetration of serous a to involve adjacent organs/tissues

Stage IV = disseminated Extranodal involvement or concomitant supra diaphragmatic nodal involvement