?Megakaryoblasts

Dear group,

we have an unusual case which we would like to share with you.
A 64 year old male, anemic with WBC around 200,000 with decreased
machine plt count but obvious large and giant atypical platelets upon
smear review. Blast count approoximately 8-12%, try tap bone marrow with
marked marrow fibrosis, negative for t(9;22).

Flow findings of peripheral blood show approximately 4-5% myeloblasts
with CD34+, CD117+, CD13+, CD33+, HLA-DR+, CD4+, CD45 dim+(tightly
clustered) with neg MPO (which we often see in MDS/MPD)

In addition however, we also see a population of about 5-7% of the
total lysed pb cells which express CD45 dim+ (spread out form negative
to dim expression) which appear as large cells in the SSvs FS histogram.
These cells appear to express CD61++, CD41++, CD33+ and CD34+, negative
for HLA-DR, CD117, CD13 and MPO.

At this point, we would like to sign out the case as a MDS/MPD with
excess blasts which alos include a portion of possible megakaryoblasts
and leave it that. However, one of the attending physicians raised the
possibility of an M7 which he could treat. Since we don't see a lot of
M7's and have very little experience with the typical patterns, we would
like some feedback as to how those populations usually present
phenotypically.
If anybody is interested in any LMD files form an FC500 or has any
suggestions, we could still do additional testing today.

Thanks so much for your feedback! 

Andrea Illingworth, MS (ASCP)
Dahl-Chase Flow Cytometry
Bangor, Maine 04401
Tel: 207-990-4855
Fax:207-945-4956
e-mail: flowlab@dahlchase.com