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 non-Hodgkin 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 populations- expanding 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

Replicating large cells found outside the germinal centers.

May be of B or T cell type Have nuclear characteristics of

replicating lymphocytes- • Vesicular chromatin • Nucleoli

Accessory cells Antigen processing cells

• Interdigitating reticulin cells- T cell paracortex• Dendritic reticulin cells- B cell germinal

centers• Process and present antigen to B and T

lymphocytes• 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

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

• Low grade

• 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 T/NK-Cell Neoplasms Hodgkin's Lymphoma•Precurso r B-ce ll lymphoblasticleukemi /a lymphoma

•Precurso r Tce ll lymphoblasticleukemi /a lymphoma

•Lym phocyte predomi ,nancenodular

Periphera l B-ce ll neoplasms Periphera -l Tce ll andNK-cellneoplasms

•Classica l HL

•B-ce ll C /LL SLL Predominantlyleu /kemicdisseminated

•Lym phocyteri ch classica l HL

•B-ce ll prolymphocyti c leukemia • -T ce ll prolymphocyti c leukemia •Nodula r sclerosis•Lymphoplasmacyti c lymphoma • -T ce ll lar ge granula r lymphocytic

(LGL) leukemia •Mi xedcellularity

•Mantl e ce ll lymphoma •N K ce ll leukemia •Lym phocyte depletion•Follicula r lymphoma •Adul t -T ce ll leukemi /a lymphoma •Unclassifiabl e classica l HL•Extranoda l margina l zone B-ce ll lymphom , a MAL T type(+/-monocytoi d B cells)

Predominant ly nodal•Angioimmunoblasti c -T celllymphoma

•Noda l margina l zone B-celllymphom a (+/-monocytoi d Bcells)

•Periphera -l Tce ll lymphomaunspecified

•Spleni c margina l zone B-celllymphom a (+/-villouslymphocytes)

•Anaplasti c lar ge ce ll lymphom ,aT/nu -ll cellPredominant ly extranodal

•Hair y ce ll leukemia •Mycosi s fungoides•Di ffuselar ge B-ce ll lymphoma •Sezar y syndrome

•Burki ttlymphoma •Primar y cutaneous(CD30+ -Tcelllymphoproliferati ve disorders)

•Plasm a ce ll myeloma • Subcutaneouspanniculitis-li ke -Tce ll lymphoma

•Plasmacytoma •N /K T ce ll lymphom , a nasa l andnasa-l type•Enteropathy- typeintestina -l Tcelllymphoma•Hepatospleni c -T ce ll lymphoma g/d (gamma/delta) a/b (alpha/beta)

REAL/WHO classification- backbone

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 lymphomasLymphomas 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 tissue- such 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 anti-apoptotic 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

FollicularLymphoma(Grade I)

Marginal zoneLymphoma

Small lymphocyticlymphoma/CLL

Frequency (%all lymphomas

22% 8 7

Age of onsetmedian

59 61 65

Stage atPresentation

Stage III/IVDisseminated

Stage I Stage IV

Response toTherapy

Good to mosttreatments,but incurableshort oftransplant

Frequently curable

Similar toFollicularlymphoma

5 yr survival 72% 74% 51%

Predominant sitepresentation

Nodal Extranodal Marrow/nodal

Pattern of nodalInfiltration

Follicular Diffuse Diffuse

Benign cellEquivalent

Germinalcentersmall cleavedcell

Marginal zoneLymphocyte

Virgin B cell

Dominant celltype

Small cleavedcell in mostcases, but canbe large cell

Mix of smalllymphocytes,plasma cells

Smalllymphocyteswith roundnucleus

Immunopheno-type

Positive: CD19 CD10, Bcl2+Negative: CD5-

Positive:CD19, Bcl2Negative:CD10, CD5

Positive:CD19, CD5CD23Negative:CD10

MolecularPathogenesis

t(14;18)Bcl2/JH

t(11;18),Trisomy 3

Trisomy 12

Examples: aggressive B cell lymphoma-Diffuse 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 children-

median 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

Bcl2

CyclinD1

Mantle cell lymphoma

Table X: Indolent B cell lymphomas

FollicularLymphoma(Grade I)

Marginal zoneLymphoma

Small lymphocyticlymphoma/CLL

Mantle cellLymphoma

Frequency (%all lymphomas

22% 8 7 6

Age of onsetmedian

59 61 65 63

Stage atPresentation

Stage III/IVDisseminated

Stage I Stage IV Stage III/IV

Response toTherapy

Good to mosttreatments,but incurableshort oftransplant

Frequently curable

Similar toFollicularlymphoma

Poor response toall therapiesto date

5 yr survival 72% 74% 51% 27%

Predominant sitepresentation

Nodal Extranodal Marrow/nodal Nodal

Pattern of nodalInfiltration

Follicular Diffuse Diffuse Diffuse,nodular or“mantle zone”

Benign cellEquivalent

Germinalcentersmall cleavedcell

Marginal zoneLymphocyte

Virgin B cell Mantle cell

Dominant celltype

Small cleavedcell in mostcases, but canbe large cell

Mix of smalllymphocytes,plasma cells

Smalllymphocyteswith roundnucleus

Small cellwith irregularnucleus,similar tocleaved

Immunopheno-type

Positive: CD19 CD10, Bcl2+Negative: CD5-

Positive:CD19, Bcl2Negative:CD10, CD5

Positive:CD19, CD5CD23Negative:CD10

Positive:CD19, CD5,Bcl2Negative:CD10

MolecularPathogenesis

t(14;18)Bcl2/JH

Trisomy 3 Trisomy 12 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+ T-

cell lymphoproliferative disorders

Subcutaneous panniculitis-like T-cell lymphoma

NK/T cell lymphoma, nasal and nasal-type

Enteropathy-type intestinal T-cell lymphoma

Hepatosplenic T-cell lymphoma

Key points regarding T cell lymphomas

Clinical Represent 20% all lymphomas More often extranodal than B

• Can involve skin, midline facial area, liver

• Very characteristic clinical presentations

Most diseases bad: high stage, and poorer response to therapy than B cell lymphomas of all grades

Pathogenesis: Characteristic cytogenetic findings

associated with several types

• Anaplastic large cell lymphoma- t(2;5): ALK1 gene

• Hepatosplenic T cell lymphoma- Isochromosome 7

Pathology Cytologic features not as predictive of

behavior as B cell lymphomas• Anaplastic large cell lymphoma -->

better prognosis than most indolent B cell lymphomas- 77% 5 year survival

• Mycosis fungoides, indolent cutaneous lymphoma, incurable, but with long clinical course

Immunophenotypic studies frequently demonstrate

• Loss of normal T cell associated antigens• Antigens associated with Natural Killer

cell function• Immunology absolutely necessary to

recognize

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 Reed-Sternberg cell, found in the appropriate microscopic cellular background

Hodgkin's lymphoma classification

Rye Classification REAL/WHO Classification

Lymphocyte predominant-5% Lymphocyte predominance,nodular

Nodular sclerosis-70%

Mixed cellularity-20% Classical HL

Lymphocyte depleted-5% 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