Page 158 - Haematologica Atlas of Hematologic Cytology

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EF Figure 5 Hairy cell cell leukemia (HCL) (A-D) Peripheral blood smears with with hairy cells (HCs) HCs HCs are are larger than normal lym- phocytes with with eccentric ovoid or or or or indented nuclei the chroma n n n n n n n n n n n n n n n n n n n is delicate and and and and nucleoli are are o o o o o o o o o o o o o o o o o o en en en en absent or or or or very small small The The abundant and and and and and clear cytoplasm may contain small small vacuoles and/or azurophilic granules and and and and and some some mes rod-shaped inclusions represen ng ng ribosome lamellar complexes The The characteris c c c c c c c c c c c c c c c c c c c feature is is is the the the the presence of ne ne and and and and short cyto- plasmic pro ec ons ons with with with with homogeneous distribu on on on on around the the the the en en en en en re re re re re re cell cell circumference giving the the the the cells their hairy appearance (E) Bu y y y y y y y coat smear with with with with many HCs HCs HCs with with with with ovoid nucleus and spongy chroma n n n n n n n n n n n n n n n n n n n n abundant cytoplasm with with with with numerous hairy pro ec ons (F) Tartrate-resistant acid phosphatase (TRAP) stain reveals strong strong reac vity of of HCs HCs HCs HCs HCs HCs have a a a a a a a a a a a a a a a a a a a a mature B-cell phenotype with expression of of of CD19 CD20 CD22 CD25 CD11c FMC7 and and strong strong surface immunoglobu- lin lin they express express the the the the speci c c c c c c c c c c an an an an gens CD103 and and Annexin1 Deposi on on on on on of of re re re re re re re culin bers in in in in in in in the the the the bone marrow (BM) areas o o o o o o o o o o o o o o en en en results in in in in in in in in in in a a a a a a a a a a a a a a a a a a a a a a dry tap In trephine sec ons the the the the HC in in in in in in in in in in ltrate may be be di di di use use or or patchy Abundant clear water cytoplasm cytoplasm or or cytoplasm cytoplasm shrinkage separates nuclei by wide margins with a a a a a a a a a a a a a a a a a a a a a a honeycomb feature This nding is is is useful to to to di di di eren ate ate ate ate HCL HCL from the the the BM localiza ons of of other types of of mature B-cell neoplasms
In HCL HCL the the the BRAF V600E muta on on on is is is o o o o o o o o o o o o o o o en en found 145