Case 13 - Discussion

Uploaded: 2007-06-29, Updated: 2007-06-29

MICROSCOPIC EXAM:

PERIPHERAL BLOOD        

Numerous blasts are present (89%). The blasts are composed by large cells with high nucleus/cytoplasm ratio, fine chromatin pattern, conspicuous nucleoli, and mild to moderate amount of basophilic cytoplasm. Many blasts 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 lysozime, focally positive for CD68, and 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 blast population expressing CD14, CD13, CD15, CD33, CD11b, HLA-DR and CD56,

       present at 81.7% of marrow cells is detected. 

CYTOGENETICS (UNMC, Cytogenetics)

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 MML region at 11q23.

IMMUNOHISTOCHEMISTRY STAINS

DIAGNOSIS

ACUTE MONOCYTIC LEUKEMIA (M5)

Clinical Futures

• >80% of the AML cells are of monocytic lineage (monoblasts, promonocytes and monocytes);
• FAB-M5a: >80% are monoblasts; 5-8% of AML, most common in young individuals; in infant, 11q23 abnormal;
• FAB-M5b: >80% are monocytes; 3-6% of AML, more common in adults;

Microscopic Findings

• Abundant cytoplasm with irregular borders, pseudopods and cytoplasmic vacuoles;
• Monoblasts have large round nuclei with one or several prominent nucleoli;
• Promonocytes have irregular folded nuclei and slightly basophilic cytoplasm with occasional azurophilic granules.

Subtypes

Differential Diagnosis

Immunohistochemistry Staining

Cytogenetics

• Trisomy 5 and/or 8;

Treatment and Prognosis

Reference

• Flow cytometry in neoplastic hematology. Wojciech Gorczyca. 2006