Page 170 - Haematologica Atlas of Hematologic Cytology

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EF CD Figure 25 25 Follicular lymphoma (FL) Old woman with di use lymphadenopathy and and WBC 259x109/L (A and and B) In blood sme- ar ar almost all all all WBC have lymphoid features: they are small with a a a a a a a a a a a scanty cytoplasm some mes visible only between the the walls of of of a a a a a a a a nuclear indenta on clumped and homogeneous chroma n n n n n n n The peculiar feature is the the the irregularity of of of the the the border of of of the the the nuclei that are cleaved (C and D) Bone marrow showing massive in in ltra on on by lymphoid cells cells smilar to circula ng ng cells cells They have a a a a a a a mature B-cell phenotype with strong expression of surface IgG they express express also the the CD10 an gen but are CD5 CD23 and CD25 nega ve ve Cytogene cs revealed t(14 18) (q32 q21) with rearragement of the BCL-2 gene gene strongly expressed by neoplas c c c c c cells (E) BCL-2 protein protein is is a a a a a a a a a mitochondrial oncoprotein that inhibits apoptosis and has a a a a a a a a a pathogene c c c c c role in in in in this disorder FL is is is a a a a a a neoplasm of follicle center cells cells (centrocytes and centroblasts) Generally only small lymphoid cells cells cor- responding to to centrocytes are are present in in in the peripheral blood and in in in rare cases leukocytosis is is conspicuous The leukemic phase of FL is is o o o o o o o o en en misdiagnosed as as chronic lymphocy lymphocy c c c c c c leukemia (F) Centrocytes (right) di di er from small lymphocytes (le ) for their smaller size the the the the clumped homogeneous chroma n n n n n n n the the the the scarce cytoplasm and the the the the nuclear indenta on 157