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Case 13 - Discussion

Hematopathology Case

 

MICROSCOPIC EXAM:

 

PERIPHERAL BLOOD        

Numerous blasts are present (89%). They are large in size with high nucleus/cytoplasm ratio, fine chromatin pattern, prominent nucleoli in subset of blasts, and moderate amount of basophilic cytoplasm. Many cells show nuclear indentation or folding, with cytoplasmic granulation, and occasional vacuoles.

     

BONE MARROW CORE BIOPSY AND CLOT SECTION:

The overall cellularity is about 50-60%. Clusters and sheets of mononuclear cells are noted with slightly indented nucleus, and they are positive for lysozyme and CD68 (subset), and are negative for CD34.

 

BONE MARROW ASPIRATE SMEAR AND TOUCH IMPRINTS:

Numerous blasts are similar to that described in the peripheral blood are seen. The estimated blast count is about 85%.

 

FLOW CYTOMETRY INTERPRETATION

 

     Total events    M gate High side scatter   A gate Bright CD45+

     analyzed=80337  Bright CD45+ events        events =3113 (5% of

                     =59537 (86% of total       total nucleated cells)

                     nucleated cells)

        CD45+/CD14-          5%                  93%

        TOTAL CD14+          95%

        TOTAL CD13+          97%

        CD34+/CD13+          <2%

        TOTAL CD15+          82% 

        CD34+/CD15+          <2% 

        TOTAL CD33+         100%

        CD34+/CD33+          <2% 

        TOTAL CD34+          <2% 

        TOTAL CD11b+         97% 

        TOTAL CD41+          <2% 

        CD34+/CD71+          <2% 

        CD34+/CD117+         <2% 

        TOTAL HLA DR+        86% 

        CD34+/HLA DR+        <2% 

        TOTAL CD19+          <2%                 15%

        CD19+/CD20+          <2%                 15%

        CD19+/CD38+          <2%                 13%

        CD19+/CD10+          <2%                 <2%

        CD2+/CD7+            <2%                 65%

        CD3+/CD5+            <2%                 68%

        CD3+/CD4+            <2%                 46%

        CD3+/CD8+            <2%                 20%

        CD3-/CD56+           68%                  7%

     

     

    FLOW CYTOMETRY INTERPRETATION:

       A blastic population account for 81.7% of events analyzed. They are positive for CD13, CD14, CD15,

       CD33, CD11b, HLA-DR and CD56, and are negative for CD34 and CD117. 

CYTOGENETICS (UNMC, Cytogenetics)

 

Positive for a reciprocal translocation involving 8p and 22q.  It is unknown whether this finding represent a constitutional abnormality or a neoplastic process. There was no evidence of the t(15;17)(q22;q11.2) in this specimen. Additional studies were also negative for a rearrangement of the MLL region at 11q23.

DIAGNOSIS

 

Acute myeloid leukemia with monocytic differentiation

 

Typically morphologic features:

 

  • Abundant cytoplasm with irregular borders, pseudopods and cytoplasmic vacuoles

  • Monoblasts: large round nuclei with fine chromatin, one or several prominent nucleoli, moderate basophilic cytoplasm, uncommon cytoplasmic vacuoles or granules

  • Promonocytes: irregular folded nuclei with moderately condensed chromatin, inconspicuous nucleoli, moderate to abundant pale-basophilic cytoplasm, cytoplasmic vacuoles and occasional azurophilic granules

  • AML with monocytic differentiation may resemble hypogranular acute promyelocytic leukemia (APL). However, leukemia cells in hypogranular APL typically have bilobated or ''butterfly-shaped" nuclei and express strong MPO by cytochemical staining and flow cytometric assay.