Page 18 - Haematologica Atlas of Hematologic Cytology

The morphological features of the the normal peripheral WBC are summarized in Table 3 For the the di eren al al al al count at least 100 elements (200 according to World Health Organiza on on (WHO) recommenda ons Swerdlow et al al 2017) should be counted to to minimize distribu on on errors If the WBC count count is is is is very high it is is is is advisable to to consider at at at least 200 cells in the case of marked leukopenia it is is advisable to to use a a a a a a a a a a PB bu y coat i i i i i i e e e e e e e e e e e e to to concentrate WBC by centrifuga on and and make bu y y y coat smears Band neutrophils neutrophils are young neutrophils neutrophils which in the di eren al should not be counted separately The possible morphological abnormali es of neutrophil nucleus or or or cytoplasm are listed in Table 4 Table 4 Qualitative abnormalities in myeloid cells Cytoplasmic
Auer rods Döhle bodies hypergranulation toxic granulation granulation granulation hypogranulation vacuolation
Nuclear
Neutrophil hypersegmentation* hyposegmentation (Perger-Huët neutrophils)
Myeloid cells in hematologic neoplasms
Myeloblasts abnormal abnormal promyelocytes monoblasts promonocytes abnormal abnormal monocytes monocytes dysplastic changes
*>3% of neutrophils with ≥5 nuclear segments A par al or or complete cytoplasmic degranula on on associated or or not with vacuoliza on on can be observed in hype- reosinophilia Monocytes are the the the largest circula ng cells It should be noted that o o o o o o o o o o o en the the the morphology of the the the leukemic monocytes monocytes does not di er er from that of the normal counterpart Immature or or atypical monocytes monocytes may be observed in in chronic myelomonocy c c c c c c c c leukemia leukemia or in in acute myeloid leukemia leukemia with monocy monocy c c c c c c c c di eren a a a a on on on on Oc- casionally granulocy c c c c c c c precursors (myeloblasts promyelocytes myelocytes myelocytes myelocytes metamyelocytes) appear in the PB The nding of circula ng ng elements more immature than a a a a a a a a metamyelocyte even if rare is always to be considered pathological except in in in the the the newborn and during pregnancy Leukemoid reac ons with the the the presence in in in the the the PB of granulocyte precursors at at various stages of matura on can be observed during severe infec ous ous or or toxic proces- ses in chronic myeloid leukemia circula ng granulocy c c c c c c c c precursors do not show evident morphological atypia so so that the the di di eren a a a a a on between leukemic and reac ve forms is o o o o en en en en di di cult The simultaneous presence in the the PB of myeloid and erythroid precursors represents a a a leukoerythroblas c c c picture The nding of of a a a a a a a a a a “hiatus” is is also an an an important diagnos c c c c feature i i i i i i i e e e e e e e e e e the co-existence of of mature cells and bla- sts sts in in the absence of of cells at at intermediate di di di eren a a a a a a a a on on stages This phenomenon suggests a a a a a a a a diagnosis of of acute leukemia The morphological di eren al al features of myeloid and lymphoid blasts will be be described in in detail in in the chapters on acute leukemias However if the blast cells are morphologically undi eren ated cytochemical and immunophenotypic criteria should be considered Table 5 Qualitative abnormalities in lymphoid cells Reactive lymphocytes
lymphocytes
Abnormal lymphocytes
Hairy cells cells lymphoma lymphoma lymphoma lymphoma cells cells (follicular lymphoma lymphoma lymphoma lymphoma mantle cell cell cell lymphoma lymphoma lymphoma lymphoma Burkitt lymphoma lymphoma lymphoma lymphoma Sézary syndrome adult T-cell leukemia/lymphoma)
Plasma cells Prolymphocytes
Smudge cells Leukemic lymphoblasts
An absolute or or or rela ve ve monomorphism of of peripheral WBC is is indica ve ve of of either acute leukemia or or or leukemic mature B- or T-cell neoplasm In chronic lymphocy c c c c c c c c c leukemia as as as a a a a a a a a a consequence of an increased cellular fragi- lity smudge cells cells are o o o o o o o en found Circula ng leukemic cells cells of the the other mature lymphoid neoplasms
may show speci c c c c c c c c nuclear and/or cytoplasmic abnormali es es es and and these will be be described in the the rela ve ve chapters In reac ve ve condi ons ons e e e e e e e e e g g g g during infec ons ons the lymphocyte morphology is is characteris c c c c c c c Lymphocytes are larger with more intense cytoplasmic basophilia more dispersed chroma n n n n n n n and some mes evident nucleolus they can also show 5