Pathology of Lymph Nodes
Norman Levy, MD
Big Picture
 As with other organs, lymph nodes, and more globally, the
immune system, can be the site of infectious, immune and
neoplastic disease, the latter either primary or metastatic
 The clinical manifestations of diseases of the lymph nodes
are:
 Local enlargement, tender on nontender, +/_
 Compression of adjacent structures +/_
 Release of cytokines producing "systemic" symptoms
of fever, weight loss and night sweats
 Infectious organisms can stimulate the same acute, chronic
or granulomatous reactions in the draining lymph nodes as
they characteristically stimulate at other sites
Big Picture 2
 Several types of immune stimuli can cause "reactive"
enlargement of the entire lymph node, or selective
expansion of cortical, paracortical or medullary regions
 Metastatic tumors spread to the lymph nodes primarily via
lymphatic drainage from adjacent solid organs
 Primary neoplasms of the lymph nodes are all malignant
 They are divided into malignant non-Hodgkin's
lymphomas (NHL), and Hodgkin lymphoma
Big Picture 3
 NHL's are more common, and can be simply divided into
indolent, or slow growing types, and aggressive types
 Malignant lymphomas represent clonal malignancies in
which mutational events have caused the majority of
progeny cells to freeze at a single stage of normal
lymphocyte differentiation
 Lymphomas frozen at a stage associated with high
replication --> aggressive lymphomas;
 Lymphomas frozen at stages associated with
recirculation or final function --> indolent lymphomas
Big Picture 4
 The diagnosis of malignant lymphomas is based on the
microscopic recognition of the dominant cytologic cell
type, supplemented by immunologic and molecular
techniques
 The treatment and prognosis of lymphomas are based on
 The dominant cell type (and it's inherent biologic
behavior),
 The extent of spread (Stage)
 The underlying health of the patient
 All of the previous statements are complicated by the fact
that indolent lymphomas can further mutate and transform
to aggressive types
Big Picture 5
 Hodgkin lymphoma is a less common nodal disease
whose diagnosis is based on the detection of a
characteristic cell, the Reed Sternberg cell, in the
appropriate histologic setting
 There are several (five) histologic subtypes, but prognosis
is based primarily on extent of disease
 Hodgkin lymphoma is a more curable disease than nonHodgkin lymphomas
 Now watch me confuse this relatively straightforward
information with the details.
Overview of the lymphoid
immune system
Lymphocytes evolve from pluripotent stem cells --> two
major functional cell types:
 B lymphocytes, comprising the humoral immune -->
production of antibodies
 T lymphocytes, comprising the cellular immune
system, -->
• Direct killing of foreign or intracellularly infected
cells, cytotoxic T cells
• Fine control of the immune response through the
secretion of cytokines, helper and suppressor T
cells.
Anatomical organization
 The anatomic organization of the lymphoid immune system
divided into two major functional regions:

The primary immune organs, sites of initial maturation -->
immune competent cells:
• B cells- bone marrow
• T cells- thymus

The secondary immune organs, sites of antigen driven
replication and differentiation into committed effector cells
• Lymph nodes
• Spleen
• Mucosal Associated Lymphoid System (MALT)- lymphoid
cells lining the respiratory and gastrointestinal tracts
• Everywhere else
 The lymph nodes, in their totality, represent the largest secondary
organ, and the major site of lymphoid pathology
Lymph node anatomy
 To recognize
lymph node
pathology,
one has to
be familiar
with normal
lymph node
anatomy
and cytology
Lymph node histology
Lymph node variation
Lymph node histology
is dynamic: follicles


In the absence of
immune stimulation,
primary follicles
In the presence of
immune stimulation,
secondary follicles or
germinal centers
Lymphocyte homing
 After initial maturation in the primary
immune organs, "virgin" B and T
lymphocytes --> peripheral blood -->
home to specific sites within the lymph
node (and the other secondary
organs),
 The sites of B cell homing include:

The primary and secondary
follicles of cortex-the sites of
• antigen presentation
• proliferation and
differentiation in response to
same

The medullary cords -->plasma
cells aggregate--> release their
immunoglobulins into the efferent
lymph
 The site of T cell homing is the
paracortex
 The separation of B and T lymphocytes
not absolute,
 Both cell types present throughout
lymph node, necessary for coordinated
lymphoid immune response.
Lymphocyte recirculation
 Normal lymphocytes recirculate, passing from blood -->
lymph nodes --> efferent lymphatics
 Allows constant surveillance for the presence of the
antigen for which the lymphocyte has a unique and
specific receptor on it's surface.
 If antigen not present, lymphocytes leave the node and
recirculate
 Virgin lymphocytes have a finite lifespan, numbered in
weeks, unless they come in contact with antigen
Cytology of the lymph node
 The normal or reactive lymph node is thus a dynamic organ
 Composed of
 Transient B and T lymphocytes
 Antigen processing and presenting cells
 Replicating B and T lymphocytes (in response to antigen)
 Persistent and transient final effector cells
 Macrophages
 Some of these functional subgroups are cytologically unique,
others cytologically indistinguishable
 The ultimate microscopic impression, with practice, is one of
cytologic heterogeneity, and histologic organization
Cell types I
 Small lymphocytes

Small round dark blue dots. Round
nucleus, clumped chromatin, small or
absent nucleolus.

The dullest looking cells hiding the
greatest level of functional
heterogeneity.
• Can be T or B cell, virgin
(unexposed to antigen) or
differentiated effector/memory cell.
• Most likely lineage, B or T,
guessed by location within the
node, but lineage and state of
differentiation must be confirmed
by immunologic/molecular
techniques


Locations:
• B cells- primary follicles,
mantle zone of secondary
follicles, medullary cords
• T cells- paracortex, minor
population within germinal
center.
Kinetically, clumped
chromatin tells us that the cell is
not proliferating- not activated
to enter the cell cycle and
replicate
Cell types 2:Follicular (germinal)
center cells
 Replicating and post-replicating B cells

Noncleaved cells, small and large
• Replicating populationsexpanding antigen responsive
cells.
• Round nuclei but larger than
resting small lymphocyte
• Open or vesicular chromatin
• Recognizable nucleoli.
– Nucleus clear -->genetic
material unwound for
replication.
• Size, large or small compared
nucleus of macrophage.

Small cleaved cells• Nonreplicating population
• Post mitotic memory or plasma
cell precursors
• Clumped chromatin
• Irregular folded and cleaved
nuclear profiles
Reactive germinal center
MZ
LZ
DZ
Cytology of lymph node 3
 Immunoblasts
 Accessory cells

Replicating large cells found

Antigen processing cells
outside the germinal centers.
• Interdigitating reticulin cells- T cell

May be of B or T cell type
paracortex

Have nuclear characteristics of
• Dendritic reticulin cells- B cell germinal
replicating lymphocytescenters
• Vesicular chromatin
• Process and present antigen to B and T
lymphocytes
• Nucleoli
• Invisible in normal lymph node

Macrophages (histiocytes)• Phagoctytic cells of lymph node
• Tingible body macrophages of germinal
centers
• Medullary and subcapsular sinus
macrophages• Abundant pale cytoplasm
• Oval nucleus, single small nucleolus
Pathology of lymph nodes 1
Infections
Reactive hyperplasias
Sarcoidosis
Metastatic tumors
Malignant lymphomas


Non-Hodgkin’s lymphoma-NHL
Hodgkin’s lymphoma
Pathology of lymph nodes 2
 Infections
 Bacterial
• Acute inflammation, abscess formation


Granulomatous, caseous and noncaseous
Diagnosis by culture, serologies, and/or special stains
Reactive hyperplasias
 Exaggerations of normal histology.

Expansion of all regions or selective expansion

Some types characteristic of certain diseases, but most not
 Follicular hyperplasia- increase in number and size of germinal centers,
spread into paracortex, medullary areas

Collagen vascular diseases

Systemic toxoplasmosis

Syphillis
 Interfollicular hyperplasia- paracortex

Skin diseases

Viral infections

Drug reactions
 Sinus histiocytosis- expansion of the medullary sinus histiocytes
Adjacent cancer

Infections
Malignant lymphomas
(Non-Hodgkin's lymphomas-NHLs)
 Malignancies of the lymphoid system which primarily
manifest themselves outside the bone marrow, at the sites
of normal lymphoid homing
 Lymph nodes
 Spleen
 M.A.L.T.
 Anywhere
(Lymphomas outside lymph nodes and spleen are
referred to as extranodal lymphomas)
 Approximately 40, 000 cases per year, 20,000 deaths
Clinical presentation
 Enlarging mass(es), typically painless, at sites of nodal tissue
 Compression, infiltration of hollow organs

Pain, obstruction, perforation
 Interference with normal organ function
Solid organ infiltration- kidneys, liver, bone marrow
 Systemic symptoms



Fever
Night sweats
Weight loss
 If marrow infiltrated, can have leukemic component
NHL 2
 Composed of cells that have lost the ability to pursue the full
range of lymphoid differentiation, and are frozen at a single
stage of the normal maturation/differentiation sequence
 Recapitulate the biology and immunophenotype of normal cell
counterpart
 Several cytologically and immunologically recognizable stages
of normal lymphoid maturation --> several subtypes of
lymphoma
 Clonal malignancies, derived from a single cell that has
undergone a malignant transformation, mutation
 Best initially conceptualized as two major clinical types
 Indolent lymphomas
 Aggressive lymphomas
NHL 3 Indolent lymphomas
 Lymphomas frozen at stages not normally replicating, but
may be circulating
 Diseases of slow accumulation, due to defective apoptosis
 Often widespread at diagnosis
 Prolonged natural history, median survivals >5 years
 Will usually respond to chemo- or radiation therapy
 Will usually relapse, but respond to same or alternative tx
 Currently incurable unless
 Localized disease or
 Marrow ablation with some type of stem cell transplant
 Classification of indolent lymphomas- later
Aggressive lymphomas
 Lymphomas frozen at stages characterized by replication and
accelerated growth
 Diseases of defective cell cycle control
 More often localized at presentation than indolent lymphomas
 More often extranodal
 Shorter natural history; median survival </= 2 years
 Require more aggressive therapy to achieve "clinical
remission"- disappearance of all detectable disease
 Despite short natural history, curable disease in some with
aggressive therapy
 Approximately 30-40% of adults
 50-80% children
 All childhood lymphomas of this type
Classification of lymphomas
 Subtyping or classification within the two groupings necessary,
because different subtypes have

Distinct clinical presentations

Can require different therapy

Have differing prognoses, reflecting different mechanisms of
molecular pathogenesis.
 Unfortunately, rarely unanimous acceptance of any one
classification scheme.
 Intermittent upgrading of classification, with new terminology,
reflecting new information and classifier bias
 Classification often lags behind advances in immunology, research
pathology
 Final result:

Difficult area to teach

Difficult to remember

Job security for me
WorkingFormulation for
Clinical Usage
• Low grade
 From 1982-1994, the classification used
in the United States
 Based on:

The observed clinical history of
1200 patients classified according to
the terminology to right

Microsopic examination alone,
utilizing
• Loss of normal nodal
architecture
• The dominant cytologic cell
type observed under the
microscope
• Presence or absence of
"follicularity" - mimicking of
normal lymphoid follicle
formation
• ML, small lymphocytic
• ML, follicular small cleaved cell
• ML, follicular, mixed small and large
cell
• Intermediate grade:
•
•
•
•
ML, follicular, large cell
ML, diffuse, small cleaved cell
ML, diffuse, mixed small and large cell
ML, diffuse, large cell
• High grade
• ML, immunoblastic
• ML, lymphoblastic
• ML, small non-cleaved cell (Burkitt's vs
non-Burkitt's)
• Miscellaneous (mycosis fungoides,
true histiocytic, etc.)
Working Formulation
 Divided into three "grades" of lymphoma- low, intermediate and
high. As stated above,

Low grade = indolent

Intermediate and high = aggressive
 Limitations

Purely morphologic classification mixed T and B cell
lymphomas together

Lumped distinct subtypes of B cell lymphomas together

Obscured the biologic, clinical and therapeutic differences

Distorted interpretation of clinical trials
R.E.A.L./W.H.O. Classification
 WF replaced in 1994 by the Revised European American Lymphoma
(REAL) classification, now being modified by the World Health
Organization (WHO)
 REAL/WHO is a "disease” oriented rather than purely morphology
oriented classification, based on:

Cell lineage: B v T v NK v Histiocytic

Stage of maturation of the presumed normal counterpart.

Includes immunologic and molecular criteria in addition to purely
morphologic criteria of WF

Each disease entity may have differing grades of aggressiveness

Greatly expanded the list of entities; includes leukemias of
lymphoid origin

Made teaching to medical students (and in fact all physicians) even
more difficult than WF
 REAL contained a number of “provisional entities” which have been
clarified in the upcoming W.H.O. revision.
B-Cell Neoplasms
Precursor B-cell lymphob last ic
leuke mia/lympho ma
T/NK-Cell Neoplasms
Precursor T cell lymphob last ic
leuke mia/lympho ma
Periphe ral B-cell neop lasms
Periphe ral T- cell and NK-cell
neop lasms
B-cell C LL/SLL
Predo minantly
leukemic/ dissemi nated
B-cell prolymphocyt ic leuke mia T- cell prolymphocyt ic leuke mia
Lymphop lasmacytic lympho ma T- cell l arge g ranu lar lymphocyt ic
(LGL ) leuke mia
Mant le cell l ympho ma
NK cell l euke mia
Folli cular lympho ma
Adu lt T- cell l euke mia/lympho ma
Ext ranoda l marginal zone B Predo minantly nodal
Ang ioimmunob last ic T- cell
cell l ympho ma, MALT type (+/monocyto id B ce lls)
lympho ma
Noda l marginal zone B -cell
Periphe ral T- cell l ympho ma
lympho ma (+/-monocyto id B
unspec ified
cells)
Splenic marginal zone B -cell
Anap last ic large ce ll l ympho ma,
lympho ma (+/-villous
T/null- cell
lymphocytes )
Predo minantly extranodal
Hairy cell l euke mia
Mycosis fungo ides
Diffuse large B -cell l ympho ma Seza ry synd rome
Burkitt lympho ma
Plasma cell myeloma
Plasmacyto ma
Primary cutaneous (CD30+ T- cell
lymphop roliferative d isorders)
Subcutaneous pann iculitis-like Tcell l ympho ma
NK/T cell l ympho ma, nasa l and
nasa l-type
Ente ropathy -type intest inal T- cell
lympho ma
Hepatosp lenic T- cell l ympho ma
g/d (gamma/de lta)
a /b (alpha/beta )
Hodg kin's Lymphoma
Lymphocyte p redo minance,
nodu lar
Class ical HL
Lymphocyte rich class ical HL
Nodu lar sclerosis
Mixed cellularity
Lymphocyte dep letion
Unclass ifiable class ical HL
REAL/WHO classificationbackbone
B cell neoplasms


Precursor B cells-related to acute leukemia
Peripheral B cell lymphomas- the majority of B
cell lymphomas
T cell and Natural Killer cell neoplasms


Precursor T cells
Peripheral T cell and NK neoplasms
Hodgkin’s lymphoma
Frequency of lymphomas
Indolent versus aggressive
 Indolent











Small lymphocytic
lymphoma/CLL
Follicular lymphoma, Grades
1/2
Extranodal Marginal zone
lymphoma of MALT type
Nodal marginal zone
lymphoma
Splenic marginal zone
lymphoma
Hairy cell leukemia
Lymphoplasmacytic
lymphoma
Plasma cell myeloma
Plasmacytoma
Cutaneous T cell lymphoma
Cutaneous CD30+ anaplastic
large cell lymphoma
Aggressive






Prolymphocytic
leukemia
Large B cell lymphoma
Burkitt lymphoma
Mantle cell lymphoma
Anaplastic large cell
lymphoma
All peripheral T cell
lymphomas
Divides B and T
B cell neoplasms- Precursor B
 Precursor B cell lymphoblastic leukemia/lymphoma
 Frozen at lymphoblast cell stage of antigen
independent B cell differentiation- normally restricted
to bone marrow
 Usually present as acute leukemia +/- lymph node
involvement
 Can initially present as node or skin disease, with later
progression to bone marrow
 Treated as acute leukemia
• 80% cure rate in children
• 20-30% in adults because of "bad" cytogenetics:
frequent presence of Philadelphia chromosome
t(9;22)
Peripheral B-cell lymphomas
Lymphomas frozen at various stages of antigen dependent B cell maturation and
differentiation
Peripheral B-cell neoplasms
 Frozen at various stages of antigen dependent B cell maturation and
differentiation

Small lymphocytic/CLL- the virgin B cell fresh from the marrow

Prolymphocytic leukemia- a more clinically aggressive variant of above

Lymphoplasmacytic lymphoma- the primary immune response

Mantle cell lymphoma- the mantle region surrounding the follicle

Follicular lymphoma- the follicle- grades 1-3

Extranodal marginal zone lymphoma- cells at the periphery of the follicle in
extranodal sites of lymphoid tissue- Mucosal Associated Lymphoid tissuesuch as G.I. tract

Nodal marginal zone lymphoma

Splenic marginal zone lymphoma- immunologically distinct

Hairy cell leukemia- pre-plasma cell

Diffuse large B-cell lymphoma- this breaks the ideal of specific cell stage
but all represent lymphomas with high replication rate

Burkitt lymphoma- very aggressive

Plasma cell myeloma- diffuse bone marrow proliferation of plasma cells

Plasmacytoma- solitary focus of monoclonal plasma cells, with variable
risk of progression to myeloma, depending on site
Example Indolent Lymphoma:
Follicular lymphoma Grade I
 Clinical







Most common type of indolent lymphoma in
US; second most common type lymphoma
overall
Disease of adults >40 (median age 59)
Usually widely disseminated at diagnosis,
incl. bone marrow
Will respond to “gentle chemotherapy” but
will relapse
• Incurable short of bone marrow
transplant unless rare limited disease
Overall 5 yr survival 72%
Over time, additional mutations -->
progression (“transformation”) to large cell
lymphoma --> aggressive clinical course
Although Gr.1 is most common presentation,
some patients present with predominance of
large cells within follicles -->more aggressive
clinical course
 Pathogenesis:

Due to t(14;18)(q32, q21)
• Upregulates expression of an antiapoptotic protein Bcl2
• Immortalizes lymphoma cells
Follicular lymphoma Grade I
 Pathology/diagnosis






Benign equivalent: small cleaved cell
of germinal center
Clumped chromatin and infrequent
nucleolus like small lymphocyte
Irregular nuclear profile, with nuclear
folds or "cleavages"
Retain follicular structure, but
monotonous accumulation of single
cell type
Characteristic immunophenotype:
• Positive:Monoclonal light chain,
CD19, CD10, Bcl2
• Negative: CD5, Cyclin D1/Bcl1
Can also detect translocation by
cytogenetics and/or polymerase chain
reaction
Table X: Indolent B cell lymphomas
Frequency (%
all ly mphomas
Age of onset
median
Stage at
Presentation
Response to
Therapy
5 yr survival
Predominant si te
presentation
Pattern of nodal
Inf iltration
Benign cell
Equivalent
Dominant cell
type
Im muno pheno
-type
Molecular
Pathogenesis
Follicular
Lymphoma
(Grade I)
22%
Marginal zo ne
Lymphoma
Small lymphocytic
lymphoma/CLL
8
7
59
61
65
Stage III/I V
Disseminated
Good to most
treatments,
but incurable
short of
transplant
72%
Stage I
Stage IV
Frequently
curable
Similar to
Follicular
lymphoma
74%
51%
Nodal
Extranodal
Marrow/nodal
Follicular
Diffuse
Diffuse
Germinal
center
small cle aved
cell
Small cl eaved
cell i n most
cases, but can
be large cell
Positive: CD19
CD10, Bcl2+
Negative: CD5-
Marginal zo ne
Lymphocyte
Virgin B cell
Mix o f small
lymphocytes,
plasma cells
t(14;18)
Bcl2/JH
t(11;18),
Trisomy 3
Small
lymphocytes
with round
nucleus
Positive:
CD19, CD5
CD23
Negative:
CD10
Trisomy 1 2
Positive:
CD19, Bcl2
Negative:
CD10, CD5
Examples: aggressive B cell lymphomaDiffuse large B cell lymphoma
 Clinical

Most common lymphoma- 30% NHL

Disease of adults and children, but median age 64

Limited versus widespread disease ~1:1

Presents with rapidly enlarging masses

Approximately 40% curable with aggressive chemotherapy/
stem cell transplant
• Partially predictable by International Prognostic Index
(later)
 Pathogenesis

Not as clearly defined as previous examples- several
cytogenetic abnormalities associated with large cell
lymphoma, but no defining one
Diffuse Large B cell lymphoma
 Pathology

Benign equivalent- large replicating B
cells of germinal center and
paracortex

Diffuse infiltration of lymph node

Often necrosis; increased mitotic rate

Cytology: Oval or cleaved nucleus with
vesicular chromatin and 1-3 nucleolus

Nucleus larger than that of reactive
macrophage

Several cytologic subtypes initially felt
to have differing clinical behavior.

Yielded division into intermediate
versus high grade types- now not felt
valid or significant without
immunologic/molecular evidence

Immunophenotype characterized by
monoclonal light chain, CD19
expression,with variable expression of
other B cell associated antigens
Burkitt's lymphoma
 Clinical

3% lymphomas

Disease of adults and childrenmedian age 31

Initially recognized in Africa by
Thomas Burkitt
• Association with Epstein Barr
virus infection
• Localization in jaw

In US, usually presents in ileocecal
region of children

1/3 of all childhood lymphomas

Earlier eras, very aggressive and
rapidly fatal
• Now, ~70-80% children curable
• 40% of adults
 Pathogenesis:

t(8;14), producing upregulation of
myc oncogene, a cell cycle
regulation gene
Burkitt's lymphoma
 Pathology

Benign equivalent is replicating small
noncleaved cell of germinal center:

Diffuse infiltration of lymph node

Very high mitotic rate, lot of
ineffective proliferation;

Attracts macrophages to
phagocytize> starry sky pattern at
low power

Cytology: round nucleus, smaller
than that of reactive macrophage

Vesicular chromatin and 2-5 nucleoli

Immunophenotype:
• Positive: Monoclonal light chain,
CD19, CD10
• Negative: CD5
Mantle cell lymphoma
 Clinical

6% lymphomas

Disease of adults (median
age 63)

Usually widely disseminated

Poor response to all
attempted therapies,

? curable with transplant

5yr survival 27%
 Pathogenesis

Due to t(11;14)

Upregulates Bcl1 (cyclin
D1), a cell cycle regulator
Mantle cell lymphoma
 Pathology/Diagnosis

Benign equivalent is lymphocyte of
inner mantle zone

Cytology similar to cleaved cell, but
nuclear irregularities not as
prominent

Nodal infiltration diffuse, vaguely
nodular or "mantle zone" around
residual benign follicles

Large cell progression infrequent

Immunophenotype:
• Positive: monoclonal light
chain, CD19, CD5, Bcl1 (and
Bcl2)
• Negative CD10, CD23
Follicular lymphoma
Mantle cell lymphoma
CyclinD1
Bcl2
Table X: Indolent B cell lymphomas
Follicular
Lymphoma
(Grade I)
22%
Marginal zo ne
Lymphoma
Small lymphocytic Mantle cell
lymphoma/CLL
Lymphoma
8
7
6
59
61
65
63
Stage III/I V
Disseminated
Good to most
treatments,
but incurable
short of
transplant
72%
Stage I
Stage IV
Stage III/I V
Frequently
curable
Similar to
Follicular
lymphoma
Poor response to
all therapies
to date
74%
51%
27%
Predominant si te
presentation
Pattern of nodal
Inf iltration
Nodal
Extranodal
Marrow/nodal
Nodal
Follicular
Diffuse
Diffuse
Benign cell
Equivalent
Germinal
center
small cle aved
cell
Small cl eaved
cell i n most
cases, but can
be large cell
Marginal zo ne
Lymphocyte
Virgin B cell
Diffuse,
nodular
or
Тmantle zoneУ
Mantle cell
Mix o f small
lymphocytes,
plasma cells
Small
lymphocytes
with round
nucleus
Frequency (%
all ly mphomas
Age of onset
median
Stage at
Presentation
Response to
Therapy
5 yr survival
Dominant cell
type
Im muno pheno
-type
Positive: CD19 Positive:
CD10, Bcl2+
CD19, Bcl2
Negative: CD5- Negative:
CD10, CD5
Molecular
Pathogenesis
t(14;18)
Bcl2/JH
Trisomy 3
Positive:
CD19, CD5
CD23
Negative:
CD10
Trisomy 1 2
Small cell
wi th irregular
nucleus,
similar to
cleaved
Positive:
CD19, CD5,
Bcl2
Negative:
CD10
t(11;14)
Bcl1/JH
T cell lymphomas-Precursor T
 Clinical

Disease of teenagers; boys>girls

Can present as acute leukemia or mediastinal mass+/- marrow
involvement

Aggressive lymphoma/leukemia, but curable: ~70% with
appropriate multiagent chemotherapy
 Pathogenesis

No single gene culprit, but frequently involve translocation of
(onco)genes to site of T cell receptor genes, --> upregulation of
proteins
T cell lymphomas-Precursor T
 Pathology




Benign equivalent
immature T cells of
thymus
Histology: Diffuse
infiltration of
thymus/adjacent lymph
nodes
Cytology: “Blast cells”
of intermediate size with
oval to “convoluted”
nuclear profiles, fine
chromatin and 0-1
nucleolus
Again need immunology
to distinguish from pre-B
Peripheral T cell lymphomas
 Predominantly
leukemic/disseminated

T-cell prolymphocytic
leukemia

T-cell large granular
lymphocytic (LGL) leukemia

NK cell leukemia

Adult T-cell
leukemia/lymphoma
 Predominantly nodal

Angioimmunoblastic T-cell
lymphoma

Peripheral T-cell lymphoma
unspecified

Anaplastic large cell
lymphoma, T/null-cell
 Predominantly extranodal

Mycosis fungoides

Sezary syndrome

Primary cutaneous CD30+ Tcell lymphoproliferative
disorders

Subcutaneous panniculitislike T-cell lymphoma

NK/T cell lymphoma, nasal
and nasal-type

Enteropathy-type intestinal Tcell lymphoma

Hepatosplenic T-cell
lymphoma
Key points regarding T cell
lymphomas
 Clinical
 Pathology

Represent 20% all lymphomas

Cytologic features not as predictive of
behavior as B cell lymphomas

More often extranodal than B
• Anaplastic large cell lymphoma
• Can involve skin, midline facial
--> better prognosis than most
area, liver
indolent B cell lymphomas- 77% 5
• Very characteristic clinical
year survival
presentations
• Mycosis fungoides, indolent

Most diseases bad: high stage,
cutaneous lymphoma, incurable, but
and poorer response to therapy
with long clinical course
than B cell lymphomas of all

Immunophenotypic studies frequently
grades
demonstrate
 Pathogenesis:
• Loss of normal T cell associated

Characteristic cytogenetic findings
antigens
associated with several types
• Antigens associated with Natural
• Anaplastic large cell
Killer cell function
lymphoma- t(2;5): ALK1 gene
• Immunology absolutely necessary to
• Hepatosplenic T cell
recognize
lymphoma- Isochromosome 7
Ancillary diagnostic studies
 Use of immunologic/molecular techniques
 Malignant lymphomas reproduce the immunobiology of their
benign counterparts
 This reproduction may be aberrant, and hence distinguishable
from normal
 Expression, normal and aberrant can be used to:

Determine lineage, B versus T versus NK

Detect clonality

Suspect malignancy- loss or aberrant expression of
expected antigens

Recognize characteristic patterns of antigenic expression
associated with certain subtypes of lymphoma
Normal lymphoid maturation
 Requires two major activities

The production of a unique
antigenic receptor on it's
surface

The expression of several
surface proteins necessary for
antigen recognition, cell
activation, cell-cell
communication.

Antigen receptors are
generated through the process
of "genetic rearrangement"- the
random selection and
juxtaposition of discontinuous
genetic segments encoding the
antigen receptor genes


B cells
• Immunoglobulin receptor
composed of two heavy
and two light chains
– Select specific heavy
chain antigen
recognition sequence
– Select only one of two
light chains, kappa or
lambda
T cells
• Select one of two
heterodimeric receptors
– Alpha/Beta
heterodimer T cell
receptor
– Gamma/Delta
heterodimer T cell
receptor
Normal lymphoid maturation
 Requires two major activities

The production of a unique antigenic receptor on it's surface

The expression of several surface proteins necessary for antigen
recognition, cell activation, cell-cell communication.
 Antigen receptors are generated through the process of "genetic
rearrangement"- the random selection and then juxtaposition of
discontinuous genetic segments encoding the antigen receptor genes

B cells
• Immunoglobulin receptor composed of two heavy chains and
two light chains
– Select specific heavy chain gene sequences
– Select only one of two light chains, kappa or lambda

T cells
• Select one of two heterodimeric receptors
– Alpha/Beta heterodimer T cell receptor
– Gamma/Delta heterodimer T cell receptor
Antigen receptor selection- B cell
Surface antigen production
 Immune cells require numerous surface molecules for
effective immune response, cell-cell communication and
regulation
 Classified into B cell associated, T cell associated, activation
associated, cytokine receptors
 Expression occurs in an orderly sequence in lymphoid
maturation
 Antibodies to these molecules cataloged thru the CD clusters of differentiation - numerical system
 Initially developed to characterize monoclonal antibodies
detecting proteins whose function was unknown .
 Now up to CD166. You'll only be tested on 1-130 though
(- a joke for you paranoid types.)
B cell antigen expression
T cell antigen expression
Immunologic Techniques
 Flow cytometry-automated
fluorescent microscopy
 Immunohistochemistry- in situ
immunologic detection
through the use of enzyme
substrate color deposition
 Both utilize monoclonal
antibodies to detect clonality
and unique antigenic patterns
Immunologic Techniques
 Flow cytometry-automated fluorescent microscopy
 Immunohistochemistry- in situ detection through the use of
enzyme substrate color deposition
 Examples
 B cell small lymphocytic lymphoma• Monoclonal light chain, CD19, CD20, CD5, CD23
positive, CD10 negative
 B cell follicular lymphoma• Monoclonal light chain, CD19, CD20, CD10
positive, CD5 negative
Molecular techniques
Detection of antigen receptor clonality
Detection of unique cytogenetic
rearrangements/translocations
Examples


Clonal gene rearrangement by Southern blot
Bcl2/JH rearrangement by polymerase chain
reaction
Clinical presentation
 Enlarging mass(es), typically painless, at sites of nodal
tissue
 Obstruction, ulceration of hollow organs- pain, perforation
 Interference with normal organ function
Solid organ infiltration- kidneys, liver, bone marrow
 Systemic symptoms



Fever
Night sweats
Weight loss
 If marrow infiltrated, can have leukemic component
Clinical staging of lymphomas
 Defines extent of disease; determines therapy and prognosis
 Based on physical, radiologic examination, bone marrow biopsy and
aspiration
 Ann Arbor Staging system
 B symptoms- fever, weight loss > 10% body weight, night sweats
Staging table
Prognosis
International prognostic index

Aggressive lymphomas
Cytogenetics
Oncogenes
International Prognostic Index 1
 Clinical features
identifying prognostic
subsets of diffuse
large cell lymphoma
 Identified through
retrospective
statistical analysis of
large set patients
 Assigned 1 point for
each bad feature
Survival curves
Therapy I Indolent lymphomas
 Seminar cases will also discuss
 Limited stage (5-10% cases)

Radiation therapy

Can be curative
 Disseminated indolent/low grade lymphomas (90%)

No therapy

Low morbidity limited chemotherapy
• Older patients
• No expectation of cure
• Most will respond totally or partially, with
months to years of disease free survival,
but will relapse
• Many will respond to additional rounds of
similar or alternative regimens
• Pts will die of disease, or interceding
disease of elderly
• Death from disease due to
– Immune suppression- infections
– Progression to aggressive lymphoma

"Bone marrow transplant"• Effort at cure
• Reserved for younger patients <60
• High dose chemotherapy and
allogeneic transplantation
• High dose chemotherapy and
autologous peripheral stem cell
collection/reinfusion
• Increased morbidity
Therapy II- Aggressive
lymphoma
 Limited disease localized disease treated with irradiation
plus limited cycles multiagent chemotherapy
 More extensive disease with more cycles multiagent (>/= 4
drugs) chemotherapy
 Complete remission rates 60-80%
 30-40% cured
 Newer therapies and their roles still being established
 Bone marrow transplantation
• Allogeneic
• Autologous
 Immunotherapy
Hodgkin's lymphoma
 Less common than NHL; ~
10,000 cases per year
 Age incidence bimodal, with one
peak in late adolescence, young
adulthood, second peak
beginning in sixth decade

Bimodal curve shifts to
younger ages in poorer
countries
 Unlike NHL, HL diagnosed by
the presence of a minor cellular
component, the ReedSternberg cell, found in the
appropriate microscopic cellular
background
Hodgkin's lymphoma
classification
Rye Classification
Lymphocyte predominant-5%
REAL/WHO Classification
Lymphocyte predominance,
nodular
Nodular sclerosis-70%
Mixed cellularity-20%
Lymphocyte depleted-5%
Classical HL
Lymphocyte rich classical HL
Nodular sclerosis
Mixed cellularity
Lymphocyte depletion
Unclassifiable classical HL
Hodgkin's Histologic subtypes
 Are characteristic patterns of
involvement, and characteristic
variants of Reed Sternberg cell
associated with different subtypes
 Nodular sclerosing HL

Most common type Hodgkin's
lymphoma in US/Europe

Usually presents in the anterior
mediastinum and neck of young
adult females

Characterized by fibrotic capsule
and bands subdividing tissue and

Lacunar variant Reed Sternberg
cell
Histologic
subtypes 2
 Lymphocyte predominant

Usually presents with limited disease in the
neck of young adults

Associated with L and H (lymphocytic and
histiocytic) or "popcorn cell" variant RS cell
 Mixed cellularity

More extensive disease

Older patients than NS and LP

More R-S cells, eosinophils, plasma cells

Mononuclear variant R-S cells

Inherently more aggressive disease
 Lymphocyte depleted

Often presents in retroperitoneum, older
patients

Accompanied by loss lymphocytes,
sclerosis and pleomorphic RS cell variants

Also more aggressive disease
Ancillary studies
 Ancillary immunologic studies assist the dx of Hodgkins' lymphoma
 Distinguish HL from

Immunoblast reactions

Unusual variants of NHL
 CD15 and CD30 antigens in golgi and on cell membrane of R-S cells
most useful
Patterns of spread
Hodgkin's lymphoma spreads contiguously via
lymphatics
Staging as in NHL- may or may not include
laparotomy/splenectomy
Therapy
Limited stage, low bulk disease treated with
radiation therapy
Higher stage, B symptoms (IIB-IV) treated with
multi-agent chemotherapy+/- radiation therapy
Complications of therapy
 Radiation effects to lungs, heart, bone marrow
 Sterility
 Splenectomy associated sepsis
 Therapy associated second malignancies
Prognosis
Hodgkin's lymphoma is a curable malignancy
Overall cure rate approximately 80%
With modern therapy, prognosis based more on
staging, bulk of disease, than morphologic subtype
Not true in earlier era, where prognosis decreased
with number of lymphocytes; lymph depleted HL
had a terrible prognosis
Pathobiology
 The etiology of HL is still unknown
 The lineage of the R-S cell was also obscure until recently
 The mixed cellular infiltrate, unusual large cells, clustered familial
cases, and early evidence of immune dysfunction suggest an infectious
etiology+/- an inherited predisposition
 In approximately 30% of cases, Epstein Barr virus found within the RS
cells
 Molecular studies, utilizing single cell dissection and PCR based
sequencing of the antigen receptor genes indicate that the R-S cell in
the majority of cases is an altered B cell.
 Thus HL is a type of B cell lymphoma, but with a very different
biology from the other types of B cell lymphoma
 Still deserves a separate category in the classification system
Molecular information
 The molecular abnormalities within the different types of
R-S variants effect the expression of lineage associated antigens

L and H cells of lymphocyte predominant HL express B cell
antigens, and are clonal proliferations of this cell type

RS cells of other types may express T cell, B cell and macrophage
associated antigens, but usually fail to express antigen receptors
• At the molecular level, show B cell gene rearrangements with out of
frame mutations or.
• Mutations in transcription/translation systems so no antigen receptor
proteins transported to surface
The End!
Additional figures
Reed Sternberg cells
Large cells