STEPTRACKERHEMATOLOGY + ONCOLOGY | PATHOLOGY | HIGH-YIELD REVIEW

Non-Hodgkin Lymphoma I — Small B-Cell

Mostly indolent B-cell lymphomas: follicular, mantle cell, marginal zone (MALT), small lymphocytic and lymphoplasmacytic.

FOCUS ON
Place each lymphoma at its stage of B-cell development, then attach its marker and translocation. Follicular = t(14;18) BCL2. Mantle = t(11;14) cyclin D1, CD5⁺ CD23⁻, aggressive. MALT = chronic inflammation (H pylori, Sjögren, Hashimoto). Small cells do not always mean an indolent course.
LYMPHOMA
CELL · MARKERS
GENETICS · ASSOCIATIONS
CLUE · COURSE
NHL — overview
Mostly B cell (~85%); painless lymphadenopathy, often extranodal.
Risk: immunodeficiency (HIV, transplant), autoimmunity (Sjögren, Hashimoto), infection (EBV, H pylori, HCV, HTLV-1)
Noncontiguous spread, unlike Hodgkin
Follicular lymphoma
most common indolent
Small cleaved centrocytes in a nodular pattern: CD20⁺, CD10⁺, BCL6⁺, BCL2⁺.
t(14;18) → BCL2 overexpression → no apoptosis
Middle-aged adult, waxing-waning painless nodes; incurable but slow; can transform to DLBCL
Mantle cell lymphoma
aggressive
Small B cells: CD5⁺, CD23⁻, CD20⁺, cyclin D1⁺.
t(11;14) CCND1–IGH
Older men; nodes, spleen, marrow, GI "lymphomatous polyposis"; poor prognosis · BTK inhibitors
Marginal zone (MALT) lymphoma
Post–germinal center memory B cells: CD5⁻, CD10⁻.
Driven by chronic inflammation: H pylori (stomach), Sjögren (salivary), Hashimoto (thyroid), C psittaci (eye), HCV (spleen) · t(11;18) resists H pylori therapy
Early gastric MALT may regress after H pylori eradication
Small lymphocytic lymphoma
Same cell as CLL: CD5⁺, CD23⁺.
Nodal presentation of CLL
Richter transformation → DLBCL
Lymphoplasmacytic lymphoma
Waldenström
Lymphocytes + plasmacytoid cells making IgM.
MYD88 L265P
IgM spike → hyperviscosity (vision, headache, bleeding), cryoglobulins, neuropathy; no lytic lesions

Mechanism — the B-cell journey and its lymphomas

Pre-B (marrow)B-ALL
→
Naive B (mantle zone)Mantle cell, CLL/SLL
→
Germinal centerFollicular, Burkitt, DLBCL
→
Memory B (marginal zone)MALT
→
Plasma cellMyeloma, Waldenström

Germinal-center lymphomas tend to be CD10⁺; the others are CD10⁻.

Telling small B-cell lymphomas apart

LYMPHOMA
CD5
CD10
KEY GENE / MARKER
Follicular
−
+
BCL2, t(14;18)
Mantle cell
+
−
Cyclin D1, t(11;14)
SLL / CLL
+
−
CD23⁺
Marginal zone
−
−
t(11;18) in some
Lymphoplasmacytic
−
−
MYD88, IgM

How it's tested

COMMON CONFUSIONFollicular lymphoma grows by cells refusing to die (BCL2). Burkitt grows by cells dividing fast (MYC). Small does not mean slow for mantle cell lymphoma.
THE TRAPA gastric lymphoma in a patient with H pylori gastritis is treated first by eradicating H pylori. Chemotherapy is not the first answer for early MALT.
YOUR APPROACHSmall B cells → CD5 and CD10 → translocation → the chronic infection or autoimmune disease behind it.

If you see… think…

Painless waxing-waning nodes, nodular pattern, BCL2⁺ → follicular lymphoma, t(14;18)
Follicular lymphoma with a suddenly enlarging mass → transformation to DLBCL
Older man, CD5⁺ CD23⁻, cyclin D1⁺ → mantle cell, t(11;14)
Multiple lymphoma polyps along the colon → mantle cell lymphoma
Gastric lymphoma with H pylori → MALT — eradicate H pylori
MALT lymphoma that doesn't respond to H pylori therapy → t(11;18)
Sjögren patient with an enlarging parotid → marginal zone lymphoma
Rapidly growing thyroid in long-standing Hashimoto → thyroid lymphoma
IgM spike, blurred vision, retinal "sausage" veins → Waldenström (MYD88)
Ocular adnexal lymphoma → Chlamydia psittaci