Page 151 - Haematologica Atlas of Hematologic Cytology

CHAPTER 16 - Precursor lymphoid neoplasms
AB
Figure 1 Hematogones (A) Bone marrow smear from a a a a a a a 5-year-old-boy three months after allogeneic cord blood transplantation performed for for T-lymphoblastic leukemia relapse Haematological data were normal with a a a a a a a a normal differential count A A moderate lymphoid infiltration is evident (B) At higher magnification small lym- phoid cells with very scanty cytoplasm round nuclei condensed homogeneous chromatin inconspicuous nucle- oli are are observed There are are also larger cells looking like blasts with loose chromatin small nucleolus scanty blue cytoplasm without granules or vacuoles Immunophenotyping showed a a a a a a a B-lineage intermediate stage phenotype (CD19+ CD20+ CD10+ CD34+ TdT+ and and Igs-) karyotype was normal normal These cells are normal normal B-cell precursors and and they are are called hematogones Hematogones are are found in in large numbers in in bone marrow aspirate specimens from normal infants and and may transiently increase in in in in older children in in in in a a a a a a a a a a a variety of congenital and and acquired disor- ders including congenital congenital neutropenia congenital congenital red blood cell aplasia iron deficiency anemia immune throm- bocytopenia non hemopoietic neoplasms
during infection They are also commonly increased in in in in regenerative marrow marrow following chemotherapy or bone marrow marrow transplantation Generally they are not present in in the the the periphe- ral blood Normal B-cell precursors may share morphological features with leukemic lymphoblasts therefore in the the context of ALL they may be misinterpreted as as residual or recurrent leukemic lymphoblasts Hematogones however are more more heterogeneous being represented at at at various maturation stages moreover they lack aberrant
or or or or asynchronous antigen expression and and do not show evidence of clonality by either cytogenetic or or or or molecular
analysis The hematologist must be be familiar with these cells and the the the conditions in in in which they may be be increased in in in the bone marrow of young children 138