Page 141 - Haematologica Atlas of Hematologic Cytology

CHAPTER 16 - Precursor lymphoid neoplasms
there is no no correlation between immunological reactivity and morphological features Genetic abnormalities including structural alterations alterations and alterations alterations involving chromosome number are ob- served in in in most ALL cases The need to to to integrate cytogenetic and molecular anomalies as as prognostic factors in in in the the classification of precursor lymphoid neoplasms
has has has been emphasized by the the WHO group who has has has defined disease entities on on the the basis of all available information including their clinical features (Table 2) The WHO group also recommends to no longer use the the the morphological distinction of ALL proposed in in the the the past by the the the French-A- merican-British (FAB) group (Bennett et et al 1976) that was based on on cell size and and on on the nuclear and and cytoplasmic features of bone marrow lymphoblasts Indeed the distinction between FAB FAB L1 and FAB FAB L2 categories has been proved not not to be predictive of of of immunophenotype of of of possible genetic alterations or of of of the clinical course and it it it is now considered to be of of little significance On the the the other hand the the the cases of of Burkitt lymphoma in leukemic phase characterized by peculiar cytological features (FAB L3 category) are no longer included among precursor lymphoid neoplasms
since they have a a a a mature B-cell immunophenotype At relapse in in in most cases the biological characteristics of lymphoblasts including morphological features are similar to those observed at onset but in in a a a a a minority of cases they change Phenotypic conversion which occurs in in 6-8% may be due to phenomena of of clonal clonal evolution clonal clonal selection or emergence of of a a a a a new independent neoplastic clone Numerous disorders both neoplastic neoplastic and non-neoplastic can mimic ALL Besides AML these include bone marrow hypoplasia or aplasia reactive lymphocytosis increase in in in hematogones especially in in in children small cell tumors of childhood and and mature B-cell neoplasms
Immunological cytogenetic and and possibly molecular criteria in in addition to a a a a a a a a a a a a careful morphological examination of peripheral blood and bone marrow smears are are essential for the differential diagnosis Table 2 orld Health rganiza on on classi ca on on of precursor lymphoid neoplasms
lymphoblas lymphoblas c c c c c leu leu emia/lymphoma emia/lymphoma not otherwise speci ed ( S) lymphoblas lymphoblas lymphoblas c c c c c c leu leu leu emia/lymphoma emia/lymphoma emia/lymphoma with with recurrent gene c c c c c c abnormali es B-lymphoblas c leukemia/lymphoma with t(9 22)(q34 1 1 1 1 q11 2) 2) BCR-ABL1 B-lymphoblas c leukemia/lymphoma with t(v 11q23 3) KMT2A-rearranged B-lymphoblas c leukemia/lymphoma with t(12 21)(p13 2 2 2 2 2 q22 1) 1) ETV6-RUNX1 B-lymphoblas c leukemia/lymphoma with hyperdiplody
B-lymphoblas c leukemia/lymphoma with hypodiploidy B-lymphoblas c leukemia/lymphoma with t(5 14)(q31 1 1 1 1 q32 1) IGH/IL3 B-lymphoblas c leukemia/lymphoma with t(1 19)(q23 p13 3) TCF3-PBX1 B-lymphoblas c leukemia/lymphoma BCR-ABL1-like*
B-lymphoblas c leukemia/lymphoma with jAMP21
T T lymphoblas lymphoblas lymphoblas c c c c leu leu emia/lymphoma emia/lymphoma Early T-cell precursor lymphoblas c c c leukemia lymphoblas lymphoblas c c c c leu leu emia/lymphoma *Provisional en ty References
Bene MC Castoldi G G G Knapp W et al al al al Proposals for for the the immunological classi ca ca ca on on of of acute leukemias European Group for for the the Immunological Characteriza on on of of Leukemias (EGIL) Leukemia Leukemia 1995 9(10):1783-1786 Benne JM Catovsky D D Daniel MT et al al Proposals for the the classi ca ca on of the the acute leukaemias French-Ameri- can-Bri sh (FAB) co-opera ve group Br Br J J Haematol 1976 33(4):451-458 Borowitz MJ Chan JKC Downing JR Le Beau MM Arber DA B-lymphoblas c c c c leukemia/lymphoma not otherwise speci ed ed ed (NOS) In: Swerdlow SH Campo E E Harris NL et al (Eds) WHO Classi ca on on on of of Tumours of of Hematopoie c c c c and Lymphoid Tissues (Revised 4th edi on) IARC: Lyon 2017 p p p p 200-202 Borowitz MJ Chan JKC Downing JR Le Beau MM Arber DA B-lymphoblas c c c c c leukemia/lymphoma with recurrent ge- ne c c c c c abnormali es In: Swerdlow SH Campo E E Harris NL et al al (Eds) WHO Classi ca on of of Tumours of of Hematopoie c c c c c 128