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Chapter 20 Non-Hodgkin lymphoma / 265

Treatment germinal follicles. It is thought that lymphoid
No treatment is required for patients without symp- hyperplasia initially occurs in response to antigen or
toms, but treatment should be started if there is infl ammation and then cells acquire secondary

significant organomegaly, anaemia, thrombocyto- genetic damage that leads to lymphoma. Th ey are
penia, neuropathy, amyloidosis or hyperviscosity. classifi ed according the anatomical site at which
Rituximab, a humanized monoclonal antibody to they arise, such as the spleen, mucosa (MALT) or
CD20 (Fig. 20.12 ), is used, generally in combina- lymph node (nodal). Mucosa - associated lymphoid

tion with cyclophosphamide, fludarabine or other tissue (MALT) lymphomas usually arise in the
purine analogue, bendamustine or bortezomib (but stomach (Fig. 20.13 ) or thyroid. Gastric MALT
is omitted if there is hyperviscosity). Combination lymphoma is the most common form and is pre-
chemotherapy as for follicular or large cell diff use B ceded by Helicobacter pylori infection. In the early
lymphoma may be needed in late stages. Autologous stages it may respond to antibiotic therapy aimed
or allogeneic stem cell transplantation (SCT) is con- at eliminating H. pylori .
sidered for advanced disease. Erythropoietin or Splenic marginal zone lymphoma usually
regular transfusions may be required for chronic presents as splenomegaly and may be associated
anaemia. with circulating ‘ villous ’ lymphocytes. Splenectomy
Acute hyperviscosity syndrome is treated with is useful for symptomatic patients.
repeated plasmapheresis. As IgM is mainly intravas- If chemotherapy is needed for marginal zone
cular, plasmapheresis is more effective than with lymphoma it is usually based on regimens used in

IgG or IgA paraproteins when much of the protein
is extravascular and so rapidly replenishes the
plasma compartment.

Marginal z one l ymphomas
Marginal zone lymphomas are low - grade lympho-
mas that arise from the marginal zone of B - cell

FcR

Neutrophil/
NK cell (a)
CD20

Rituximab
B cell Complement (b)
(Anti-CD20)

(c)

Figure 20.12 The potential mechanisms of action of

rituximab. Rituximab binds to CD20 on the surface of Figure 20.13 Gastric mucosa - associated lymphoid
B cells. It can elicit a number of effector mechanisms tissue (MALT) lymphoma: the tumour cells surround
including: (a) antibody dependent cell - mediated reactive follicles and infi ltrate the mucosa. The follicle
cytotoxicity; (b) complement mediated lysis of tumour has a ‘ starry sky ’ appearance. (Courtesy of Professor
cells; and (c) direct apoptosis of the target cell. P. Isaacson.)