>Hi, I have seen a couple of B-precursor ALL cases with very weak (could be interpreted as negative) CD19 positivity and positivity for CD10/TdT. In these cases the cyt. CD22 and/or cyt.CD79 were positive (stained with APAAP method on cytospins) proving the B lineage. Your case might be similar to those. Best wishes Anna Porwit-MacDonald MD, PhD Haematopathology Lab, Karolinska Hospital, Stockholm >To all clinical flow people, > >We have had an unusual case of an 0acute leukemia which I would like to >share with you, hoping you have seen something like this before and can >explain our flow findings. > >This is a 7 year old female with the following CBC findings: >WBC: 15.3 >RBC: 3.26 >Hgb: 9.5 >Plt: 26,000 >blasts: 16% > >Cytochemistry: negative for myeloperoxidase >The CSF showed also leukemic infiltrate. > >Review of the marrow aspirate shows a predominance of blasts. The blasts >range in size from small to large with occasionally prominent nucleoli and >generally scant cytoplasm. No Auer rods are identified. > >Flow cytometric analysis showed the blasts to have both increased FALS and >SS and to be positive for CD45 (weak to moderate), CD10 (weak to moderate), >and TdT. CD19 was negative!! The blasts were also negative for CD2, CD5, >CD7, CD13, CD15, CD33, CD11c, and CD34. There was some weak positivity for >CD20 and cytoplasmic IgM which I am inclined to interpret as >negative/non-specific. >DNA content analysis showed a near tetraploid/DNA aneuploid population with >a DNA Index of 1.95. > >This case was signed out as acute lymphoid leukemia with undifferentiated >phenotype. > >We were really puzzled by the absence of CD19 as well as by the high DNA >Index in a B-ALL. Also, aren't undifferentiated ALL's usually CD45 negative? > > >If you have ever encountered a case like this, we would greatly appreciate >your input! >Andrea Illingworth >Dahl-Chase Diagnostic Services/Flow Cytometry >333 State Street >Bangor, Maine 04401 >(207)990-4855 > > >
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