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LYMPHOID NEOPLASMS. Definitions and Classification One confusing aspect concearns the use of the term LEUKEMIA and LYMPHOMA. LEUKEMIAS present with widespread involvement of the bone marrow and peripheral blood . LYMPHOMA is used for proliferations arising as discrete tissue masses .
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Definitions and Classification Oneconfusingaspectconcearnstheuseofthe term LEUKEMIA and LYMPHOMA. LEUKEMIAS presentwithwidespreadinvolvementofthe bone marrow and peripheralblood. LYMPHOMA isusedforproliferationsarisingasdiscretetissuemasses. Originally, terms LEUKEMIA and LYMPHOMA wereconsistentdistinctentities, butthisdivision has blurred. Manylymphomasmayhaveleukemicpresentations and evolution to leukemiasisnotunusual. Conversely, leukemiassometimesariseassoft-tissuemasses. Bothtermsmerelyreflecttheusualtissuedistributionofeachdiseaseatpresentation.
LYMPHOMAS are known in twocategories: Hodgkin´sLymphoma, treatable in a uniquefashion, and thefamilyofNHL. Theclinicalpresentationofthevariouslymphoidneoplasmsis most oftendetermined by theanatomicdistributionofthedisease. 2/3 ofNHLs and virtuallyall HL presentasenlargednon-tenderlymphnodes (› 2 cm). Theremaining 1/3 ofNHLspresentwithsymptomsrelated to involvementofextranodalsites: stomach, intestine, skin, brain. In NHL animportantgroupoftumorsisrepresented by theplasmacellneoplasms. Leukemiaspresentwithsymptomsrelated to thesupressionofhematopoesis. Multiplemyelomacauses bony destruction or paindue to pathologicfracture. Certaintumorsmay cause fever (HL) andsecretionofcirculatingfactors (e.g.amyloid) from plasma cells.
HISTORY Theoldestclassificationscheme has usedonlyfewterms: lymphosarcoma, reticulosarcoma, lymphogranulatomasisPaltauf-Sternberg, M. Hodgkin. Rappaport: nodular– difuse involvementofthelymphnodes. Duringtheyears 1960 – 1980 theretemporarilyexistedseveralnationalclassifications (German, French, English, American (Florida andCalifornia) andinternational (REAL) , introducingnew basic andresearch-basedandclinicallyacceptedinformation. Soonafterwards, attheendofthe 20th century, WHO expertsfromseveralmedicalspecialitieshavedeveloped a unified, modernandopen internationalclassificationsystem (2001) based on morphological, immunophenotypic, genotypicandclinicalfeatures(interdisciplinaryacepted).
The WHO ClassificationofLymphoidNeoplasms (2001) I Precursor B Cell Neoplasms B cell acutelymphoblasticleukemia/lymphoma (B - ALL) II Peripheral B Cell Neoplasms Chroniclymphocyticleukemia/smalllymphocyticlymphoma B cell prolymphocyticleukemia Lymphoplasmocyticlymphoma Splenicandnodalmarginalzonelymphoma Extranodalmarginalzonelymphoma Follicularlymphoma Marginalzonelymphoma Hairy cell leukemia Plasmacytoma/plasma cell myeloma Diffuselarge B cell lymphoma Burkittlymphoma
The WHO ClassificationofLymphoidNeoplasms (2001) III Precursor T cell neoplasms T cell acutelymphoblasticleukemia/lymphoma (T – ALL) IV Peripheral T cell and NK cell neoplasms T cell prolymphocyticleukemia Largegranularlymphocyticleukemia Mycosisfungoides/Sézary syndrome Peripheral T cell lymphomaunspecified Anaplasticlarge cell lymphoma Angioimmunoblastic T cell lymphoma Enteropathy-associated T cell lymphoma Panniculitic T cell lymphoma Hepatosplenicgamma-delta T cell lymphoma Adult T cell leukemia/lymphoma Extranodal NK/T cell lymphoma NK cell lymphoma
The WHO ClassificationofLymphoidNeoplasms (2001) • V Hodgkinlymphoma • Classicalsubtypes • Nodularsclerosis type • Mixedcellularity type • Lymphocyte-richtype • Lymphocytedepletiontype • Lymphocytepredominance type
Importantprinciplesoflymphoidneoplasms • Lymphoidneoplasmsmaybeclinicallysuspected, buthistologicexaminationisrequiredfordiagnosis. • In most lymphoidneoplasms, antigen receptor gene rearrangementpresentstransformation, hence, allofthedaughtercellsderivedfromthemalignantprogenitorsharethesameconfigurationandsequence, andsynthesiseidentical antigen receptor protein (Ig, T cell receptor). In contrast to reactive (polyclonal) proliferationsthelymphoidneoplasms are monoclonallymphoidproliferations. • These antigen gene rearrangementproduce a unique DNA sequencesthatconstitute a highlyspecificclonalmarker, detectable by MoAb. • Thevast majority (85-90%)oflymphoidneoplasms are of B-cell origin.
Importantprinciplesoflymphoidneoplasms NK tumors are rare. B cell and T cell representsomerecognizablestageof B or T cell differentiation, a feature used in theirnomenclature/terminology. Benigncounterpartsoflymphomas do not exist. NeoplasticB and T cellsrecapitulatethebehaviouroftheirnormalcounterparts. Examples: follicularlymphomashome to germinalcenters, cutaneouslymphomashome to the skin. Thisisgoverned by particularadhesionmoleculesandchemokinereceptors. Variablenumer of B or T cellsrecirculatethroughthelymphaticsandbloodvessels, sothatattimeofdiagnosis most tumors are widelydisseminated. Exceptions: HodgkinlymphomaandMarginalzone B cell lymphoma. This feature remindsofthephysiologicaldailyrepeating multiple recirculationoflymphocytesbetweenthecentralandperipherallymphaticorgans. Hodgkinlymphomaspreads in anorderlyfashion. In contrast, most formsof NHL spreadwidelyearly in theircourse in a lesspredictablefashion. Therefore, stagingisof most utility in HL.
PRECURSOR B cell and T cell neoplasms are composedofimmature B and T cells (lymphoblasts). About 85% are B-ALL anditisthe most commoncancerofchildrenup to 15 years. Adults are affectedlessfrequently. Individualcasesmaybe more orlessimmatureormature, sothatvarious CD markers: B: CD 10, 19, 20 andT: CD 1,2,3, 4, 5, 7 and 8 maybeexpressed in tumor cells. Approximately90% ofALLshavevariousnumericalorstructuralchromosomalchanges. PediatricALL isoneofthegreatsuccessstoriesofoncologywithcompleteremission in 95% ofchildrenand 30-40% ofadults. Clinicalfeatures: abruptonset, depressionof bone marrowfunctions, masseffect, CNS manifestations.
Peripheral B-cell Neoplasms ChroniclymphocyticLeukemia (CLL)/SmalllymphocyticLymphoma (SLL) Representsthe most commonadultleukemiawithmedianageatdiagnosisbeing 60 years, 2:1 male preponderance in Western countriescomparingwithAsiancountriesand Japan. Microscopically: diffuseinfiltrationwithsmalllymphocyteswithproliferationcenters in thelymphnodes, bone marrow, spleen and liver. Expressionof CD 19, 20, 23 and 5, surfaceIgM. Clinically, fatigability, anorexia, weightloss, lymphadenopathy, hepatosplenomegaly, hypogammaglobulinemia, relativelyslowcourse , tendency to transformation to more aggressiveforms (Richter syndrome). Possible use ofimmunotherapy, chemotherapyandtransplantation.
FollicularLymphoma • Anindolent ,most common NHL in middleagewithunevenfrequency in the Word. • Typicalcell is a smalllymphocytewithirregular/cleavednuclei (centrocyte) in predominantfollicular arrangement. • Immunophenotype:CD 10, 19, 20, surfaceIg, BCL 6. • Clinically: generalized, painlesslymphoadenopathy, andrelativelyuncommoninvolvementofextranodalsites. Mediansurvival: 7-9 years, withpossibletransformation to diffuselargeB cell lymphoma(durationlessthan 1 year).
Diffuselarge B-cell Lymphoma • Themost common NHL withmedianageof 60 years, mayaffectevenchildren. • Microscopicallythese tumorsgrowdiffuselyandcontainrelativelylargecells. • Immunophenotype: CD 19, 20, sometimesalso CD10 and BCL-6. • Cytogeneticgene expressionisheterogenous. • Specialforms: Immunodeficiency-associatedlarge B cell LymphomaandPrimaryeffusionlymphoma in AIDS andelderly. • Ifuntreated, isanaggressive tumor affecting many sitesandrapidlyfatal. • Immunotherapyimprovesresponsesandoutcome/prognosis.
BurkittLymphoma (BL) • African(endemic) BL • Sporadic (non-endemic) BL • Aggressivelymphoma in AIDS • Microscopically: a starry-skyappearance, highmitoticindex • Immunophenotype: CD 10, 19, 20, BCL-6, sIgM • Molecularpathogenesis: Translocationsofthe C MYC gene on chromosome 8 • EndemicandsporadicBLsare formedmainly in childrenandyoungadultsmostly in extranodalsites (mandible, kidneys, ovaries, adrenals) Tumorsare aggresivebuttreatable
Plasma Cell NeoplasmsandRelatedDisorders(dyscrasias) Containplasma cellssecretingmonoclonalIgor a Ig fragment. Theworst type isMultiple myeloma (plasma cell myeloma). Specialterms are usedfor these neoplasms: monoclonalgammopathy, dysproteinemia, paraproteinemia, primaryamyloidosisorimmunocyte-associatedamyloidosis. Plasmocytoma(solitarymyeloma)isaninfrequent variant thatrepresentsas a single (isolated) mass in bone or in soft tissue. Smolderingmyelomawithlackofsymptomsandhigh plasma M. component. Waldenströmmacroglobulinemiais a syndrome: monoclonalgammopathy, bloodhyperviscosityandincurablelympho-plasmocyticlymphoma. HeavychaindiseaseandMonoclonalgammopathyofundeterminedsignificance (MGUS), common in elderly, with a constantrateoftransformation to myeloma.
Mantle Cell Lymphoma Isa rare, prognosticallypoorformoflymphomawithpainlessgeneralizedlymphadenopathy in elderlywith male predominance. Smallcellsresemblethenormal mantle zone B cellssurrounding germinalcenters. Immunophenotype: CD 5, 19, 20, cyclinD1. MarginalZoneLymphoma Encompassesa heterogenousgroupof B cell tumorsarisingwithinlymphnodes, spleen orextranodally (e.g. mucousmembranes, „maltoma“). Theyoftenarisewithintissuesinvolved by chronicinflammatorydisordersofautoimmune (Sjögren, Hashimoto) orinfectious etiology (H. pylori) withpossibleregressionfollowingsuccessfultreatmentof H. pylori.
Hairy Cell leukemia Isa rare, distinctive B cell NHL (2%) withmassivesplenomegalyandfrequentinfections. Males are affected more frequently (5:1), medianageis 55 years. Overallprognosisisexcellent. Immunophenotype: CD 11c, CD 19, 20, 25 and 103. PeripheralT cell and NK cell Lymphomas Becauseofproblemswithcategorization, many forms are classified as Peripheral T cell Lymphomas, unspecified. These tumorseffacelymphnodesdiffuselyand are composedofpleomorphicmixtureofvariouslysizedmalignant T cellsandintensveangiogenesis. Immunophenotype: CD 2, 3, 4, 5, 8, andalpha/beta orgamma/delta T cell receptors. These tumorspresentwithgeneralizedlymphadenopathy, weightloss, fever, andeosinophilia.
AnaplasticLarge cell Lymphoma(ALK positive) • Iscomposedofanaplasticlargecellswithhorseshoe-shapednuclei, so-called„HALLMARK CELLS“, mimickingmetastaticcarcinoma. • Immunophenotype: ALK cytoplasmicfusionprotein expression, a reliableindicatorofan ALK gene rearrangement. • These tumorsoccur in childrenandyoungadults, involve soft tissuesandcarry a verygoodprognosis. • AdultT cell Leukemia/Lymphoma • Thisadult tumor is a rapidlyprogressivediseasedespiteaggressivetherapy. ItdevelopsafterinfectionwithHTLV-1 (retrovirus) in specificgeographicareas. In someinstances, thisinfectionmaygiverise to a progressivedemyelinizatingdiseaseofthe CNS andspinal cord.
MycosisFungoides/Sézary Syndrome Are differentmanifestationsof a CD4+ helper T cell diseaseaffecting skin (MF) withthreestages: premycoticinflammatorystage, plaquephase, and a tumor stagewithsimultaneousinvolvementoflymphnodesand bone marrow. In Sézary syndrome the skin manifestationsrepresentgeneralizedexfoliativeerythrodermaandleukemiawithcerebriformnuclei in peripheralblood. These are indolenttumors (up to 9 years) withimmunophenotype: adhesionmoleculeCLA, chemokine receptor CC4, CCR 10, and CD4 T cell. Largegranule LymphocyticLeukemia Rarein twovariants (T cell, CD3, indolent) and (NK, CD56, more aggressive) ofanadultdisease. Despitetherelativepaucityofmarrowinfiltration, neutropeniaandanemiadominatetheclinicalpicture. ExtranodalNK/T cell Lymphoma Israre in Europeand USA and more frequent in Asia. Presents as a destructivenasopharyngealmass in associationwith EBV infection, alsoaffectingtestisand skin. Surroundingandinfiltratingsmallvessels, itleadsto extensiveischemicnecroses. This tumor ishighlyaggressiveandwithpoorprognosis.
HODGKIN LYMPHOMA Isa groupoflymphoidneoplasmsdifferingfrom NHL in severalrespects. Themaindifferences are tabularized: IdentificationofReed-Sternbergcells(andtheirvariantsand „mumification“) in a prominent background of a groupofinflammatorycellsisprincipalforthediagnosis.
HODGKIN LYMPHOMA Immunophenotypefor 1-4: CD 15, 30, PAX5, excellentorlessfavorableprognosis, for 5: CD 20, BCL6. RS cellsproducesignals (cytokines IL-5, 10,13, TGF-beta) andchemokines (ARC, MDC, IP-10, CCL-28), thatattractreactivecells. Onceattracted, thereactivecellsproducefactorsthat support thegrowthandsurvivalof RS cells, furthermodifyingthereactive cell response. Clinicalfeaturesof HL Painlesslymphadenopathy, fever, nightsweats, weightloss, immunedysregulation, dyspnoe, etc. Thespreadisremarkablystereotyped: nodes, spleen, liver, othertissues. Thestaging not onlydeterminestheprognosis, butalsoguidestherapy. Radiationtherapymaybecurative in many patients.
HODGKIN LYMPHOMA StagingofHL I Involvementof a single node or a single extranodal organ site II Involvementof 2 or more lymphnode regions on thesamesideofdiaphragm III Involvementoflymphnode regions on bothsidesofdiaphragmwithoutlocalizedinvolvementofanextralymphatic organ/site IV Diffuseinvolvementof 1 or more extranodalorgans/siteswithout/withlymphaticinvolvement Additionalfeaturesincludedintostagingprocedure: fever, kachexia, nightsweats Withcurrentprotocols, tumor stage (betterthanbiopsy) isthe most importantprognosticvariable. Survivalofstage I-II – 90%, III-IV – 60-70%. Increasedrisk ofsurvivors by secondcancers, especiallybecauseofappliedirradiationtogetherwithfibrosisandatherosclerosis, whichcanbeavoided by moderntherapy.