256
U N I T 3
Hematopoietic Function
As with NHL, the cause of Hodgkin lymphoma is
largely unknown. Although exposure to carcinogens
and viruses as well as genetic and immune mechanisms
have been proposed as causes, none has been proven to
be involved in the pathogenesis of the disease. It appears
that people with a history of infectious mononucleosis
are at increased risk for the development of Hodgkin
lymphoma.
4,7,45
Classification.
The WHO classification proposed clas-
sifying Hodgkin lymphoma into two major categories:
nodular lymphocyte-predominant Hodgkin lymphoma
and classic Hodgkin lymphoma.
4,45
Nodular lympho-
cyte-predominant Hodgkin lymphoma represents only
a small portion of all cases of HL and is a unique form
that generally exhibits a nodular growth pattern, with
or without diffuse areas and with rare Reed-Sternberg
cells called “popcorn” or “L&H” (lymphohistiocytic)
cells. It is often localized rather than disseminated at the
time of diagnosis, exhibits a slowly progressive course,
and has an overall survival rate greater than 80%.
4
Classic Hodgkin lymphoma is characterized by
clonal proliferation of typical mononuclear Hodgkin
cells and multinucleated Reed-Sternberg cells with
invariable expression of CD30. Four variants of classic
Hodgkin lymphoma have been described: nodular scle-
rosing, mixed cellularity, lymphocyte rich, and lympho-
cyte depleted. The nodular sclerosing type is the most
common and is often found in adolescent and young
adult women, 15 to 35 years of age.
4
Lymphocyte-
rich Hodgkin lymphoma is a newly defined entity, and
lymphocyte-depleted Hodgkin lymphoma is rarely
diagnosed. At present, all subtypes of classic Hodgkin
lymphoma are treated in the same manner.
46
Clinical Manifestations.
Most persons with Hodgkin
lymphoma present with painless enlargement of a single
node or group of nodes. The initial lymph node involve-
ment typically is above the level of the diaphragm (i.e.,
in the neck, supraclavicular area, or axilla). Mediastinal
masses are frequent and are sometimes discovered on
routine chest radiography. There may be complaints of
chest discomfort with cough or dyspnea. Involvement
of subdiaphragmatic lymph nodes at the time of
presentation is unusual andmore common in elderlymen.
Additional symptoms that suggest Hodgkin lymphoma
include fevers, chills, night sweats, and weight loss.
Pruritus and intermittent fevers associated with night
sweats are classic symptoms of Hodgkin lymphoma.
Other symptoms such as fatigue and anemia are
indicative of disease spread. In the advanced stages of
Hodgkin lymphoma, the liver, spleen, lungs, digestive
tract, and, occasionally, CNS may be involved. As the
disease progresses, the rapid proliferation of abnormal
lymphocytes leads to an immunologic defect, particu-
larly in cell-mediated responses, rendering the person
more susceptible to viral, fungal, and protozoal infec-
tions. Anergy, or the failure to develop a positive
response to skin tests such as the tuberculin test, is com-
mon early in the course of the disease.
Diagnosis and Treatment.
A definitive diagnosis of
Hodgkin lymphoma requires that the Reed-Sternberg
cell be present in a biopsy specimen of lymph node tissue.
Computed tomography scans of the chest and abdomen
commonly are used to assess for involvement of medi-
astinal, abdominal, and pelvic lymph nodes.
44
If with
initial screening the extent of lymph node involvement
cannot be determined, PET imaging may be helpful.
Persons with Hodgkin lymphoma are staged accord-
ing to the number of lymph nodes involved, whether the
lymph nodes are on one or both sides of the diaphragm,
and whether there is disseminated disease involv-
ing the bone marrow, liver, lung, or skin. The staging
of Hodgkin lymphoma is of great clinical importance
because the choice of treatment and the prognosis ulti-
mately are related to the distribution of the disease. In
addition, patients are designated stage A if they lack
constitutional symptoms and stage B if 10% weight loss
(over 6 months) or night sweats are present.
Irradiation and chemotherapy are used in treating the
disease. Most people with localized disease are treated
with radiation therapy
46,47
whereas a combined approach
using radiation and chemotherapy is used in persons with
advanced disease. As the accuracy of staging techniques,
delivery of radiation, and curative efficacy of combination
chemotherapy regimens have improved, the survival rate
of people with Hodgkin lymphoma also has improved.
Plasma Cell Dyscrasias
Plasma cell dyscrasias are characterized by expan-
sion of a single clone of immunoglobulin-producing
plasma cells and a resultant increase in serum levels of
a single monoclonal immunoglobulin or its fragments.
The plasma cell dyscrasias include multiple myeloma,
lymphoplasmacytic lymphoma, and monoclonal gam-
mopathy of undetermined significance.
Monoclonal
gammopathy of undetermined significance
(MGUS)
is characterized by the presence of the monoclonal
immunoglobulin in the serum without other findings
of multiple myeloma. Monoclonal gammopathy of
undetermined significance is considered a premalignant
condition.
4,7
Approximately 2% per year of persons
FIGURE 11-9.
Classic Reed-Sternberg cell; photograph shows
normal lymphocyte compared with Reed-Sternberg cell. (From
National Cancer Institute Visuals. No. CDR576466.)
