MAURILIO(PONZONI((MILAN)(
DIAGNOSTICS
Marginal!zone!B>cell!lymphomas!(MZL)!include,!according!to!WHO!classification,!extranodal!
MZL!of!MALT!type!(EMZL),!splenic!MZL!(SMZL)!and!nodal!MZL!(NMZL).!EMZLs!arise!in!organs,!
like!stomach!and!ocular!adnexa,!usually!in!the!context!of!chronic!infective,!autoimmune!or!
unknown! stimuli.! The! updated! 2017! WHO! classification! recognizes! SMZL! as! a! distinct!
lymphoma! and! the! splenic! B>cell! lymphoma/leukemia! unclassifiable! (SLL>u)! as! provisional!
entity,! respectively:! SLL>u! include! splenic! diffuse! red! pulp! lymphoma! (SDRPL),! hairy>cell!
leukemia!variant!(HCL>v),!and!unclassifiable!forms.!!
Histopathologically,! MZL! encompass! small,! centrocytic>like! or! monocytoid! B! lymphocytes,!
sometimes!associated!with!plasmacytic!differentiation!or!intermingled!blasts,!and!associated!
with! a! variable! amount! of! reactive! non>neoplastic! elements,! including! reactive! germinal!
centres,! T>lymphocytes! and,! in! mucosa>associated! sites,! epithelium.! At! the! microscope,!
differentiating! MZLs! from! the! other! B>cell! lymphomas! is! frequently! a! problem! for!
pathologists! in! routine! practice,! mostly! for! the! paucity! of! invariably! specific! positive!
immunohistochemical!markers!(diagnosis!of!MZL!still!nowadays!relies!om!exclusion!criteria)!
and!the!resemblance!to!other!mimicker!lymphomas.!The!main!histopathological!problems!in!
MZLs! involve:! i)! the! differentiation! from! non>lymphomatous! disorders;! ii)! the! distinction!
from! other! B>cell! lymphomas,! which! varies! across! different! anatomical! sites;! iii)! the!
transformation!into!large!B!cell!lymphoma!(DLBCL).!!
Reactive!conditions!may!be!difficult!to!distinguish!from!MZLs.!Some!pediatric!cases!of!nodal!
marginal!zone!hyperplasia,!recently!associated!with!Haemophilus!influenzae!infection,!could!
precede! some! pediatric! NMZL! and! sometimes! the! border! between! these! two! disorders! is!
not!sharp.!Some!examples!of!Helicobacter!Pylori>induced!florid!follicular!chronic!gastritis!not!
only! anticipate! the! development! of! MALT! lymphoma! but! could! mimic! a! lymphoma.! In!
controversial!cases,!flow!cytometry,!PCR,!and,!recently,!expression!of!some!miRNAs!could!be!
helpful.!!
Pediatric! NMZL! is! a! provisional! entity! in! the! updated! WHO! classification! with! distinct!
clinicomorphological! features! and! excellent! prognosis.! This! lymphoma! usually! occurs! in!
young!males!as!a!localized!cervical!lymphadenopathy.!Histologically,!large!follicles!with!florid!
proliferation! of! marginal! zone! cells! and! disruption! of! germinal! centers! (GCs),! mimicking!
progressively! transformed! GCs,! are.! ! Clonal! rearrangement! of! the! IGHV! region! is! detected!
almost!in!each!case.!!
Differentiation! of! NMZL! and! EMZL! from! follicular! lymphoma! (FL)! can! be! challenging,! in!
particular!for!t(14;18)>negative!FLs.!Immunophenotypical!characterization!must!be!managed!
with! caution! because! putative! ‘specific’! GC! markers! like! Bcl6,! LMO2! and! HGAL! could! be!
occasionally! present! in! NMZL! as! well.! Although! some! positive! markers! for! MZL! have! been!
proposed,!including!IRTA1,!MNDA,!TCL1A!and!CD180,!none!are!selectively!expressed!by!this!
lymphoma.!At!the!molecular!level,!in!NMZL,!the!selective!defects!in!PTPRD!gene!have!been!
recently! reported! in! 20%! of! patients,! as! well! as! alterations! of! the! NFkB! pathway,! while!
TNFRSF14! mutation! has! been! proposed! as! exclusive! for! FL.! In! the! spleen,! SMZL! and! SLL>u!
may!show!sometimes!morphological!overlap!with!primary!splenic!FL.!!
Differentiation!from!lymphoplasmacytic!lymphoma!(LPL)!requires!integration!of!clinical!and!
laboratory! data.! LPL! is! characterized! by! elevated! serum! IgM! paraprotein! and! frequent! BM!
infiltration.!In!lymph!nodes,!a!marginal!zone!pattern!of!involvement!by!monocytoid!cell!and!
SCIENTIFIC PROGRAMME
SESSION I
HODGKIN’S DISEASE
DEBATE I
IS THERE STILL A ROLE
FOR COMBINED MODALITY
THERAPY FOR EARLY
STAGE CHL?
SESSION II
T-CELL LYMPHOMA
ROUNDTABLE I
FUTURE DIRECTIONS IN
T-CELL LYMPHOMA
SESSION III
FOLLICULAR LYMPHOMA
DEBATE II
CAN WE AVOID
CHEMOTHERAPY IN
THE MANAGEMENT OF
FOLLICULAR LYMPHOMA?
SESSION IV
RARE LYMPHOMAS –
MARGINAL ZONE
LYMPHOMA AND
WALDENSTRÖM M
ACROGLOBULINEMIA
ROUNDTABLE II – WHERE
TO GO IN RARE B-CELL
LYMPHOMAS
SESSION V
MANTLE CELL LYMPHOMA
SESSION VI
DIFFUSE LARGE B-CELL
LYMPHOMA
DEBATE III
DO WE STILL NEED ASCT
IN MCL?
SESSION VII
NOVEL THER APEUTIC
CONCEPTS IN B-CELL
LYMPHOMAS
SELECTED ABSTRACTS
FOR AN ORAL
PRESENTATION
SELECTED ABSTRACTS
FOR A POSTER
PRESENTATION
DISCLOSURES