Case 24 - Discussion

Uploaded: 2007-09-20, Updated: 2007-09-20

MICROSCOPIC EXAM:

PERIPHERAL BLOOD        

Examination of the Wright-Giemsa stained peripheral blood reveals markedly increased blasts (76%) with high N:C ratio, fine and delicate chromatin, and scant amount of blue cytoplasm. Some of the blasts have prominent nucleoli. There are no granules identified in the cytoplasm. Occasional hypolobated neutrophils and bands are noted. Mild normocytic anemia is present. Platelets are decreased in number. Some of the platelets are large and show hypogranulation.

BONE MARROW CORE BIOPSY AND CLOT SECTION:

The bone marrow is hypercellular (80-90%), and diffusely infiltrated by blasts. The blasts are medium to large in size with delicate chromatin and moderately abundant pink cytoplasm. Frequent mitotic figures are present. There are rare erythroid precursors. Megakaryocytes are focally increased in number with dysplastic morphology. PAS stain highlighted megakaryocytes and rare mature neutrophils. Moderate to severe diffuse reticulin fibrosis is identified on reticulin stain. Iron storage is focally increased on iron stain.     

BONE MARROW ASPIRATE SMEAR AND TOUCH IMPRINTS:

The bone marrow aspirate smears and touch imprints are hypercellular with speckles and are adequate for evaluation. Blasts are markedly increased in number (estimated at 80%). The morphology of the blasts are similar to the peripheral blood blast described above. Rare myelocytes, metamyelocytes, bands and occasional mature neutrophils are noted. Scattered erythroid precursors with unremarkable morphology are noted. Scattered lymphocytes and rare megakaryocytes are present.

FLOW CYTOMETRY INTERPRETATION

Specimen: Peripheral Blood

The dim-CD45 positive events represent blastoid population and account for about 70% of total viable events analyses. These blasts are positive for myeloid markers CD13, CD33, CD117, and cMPO. Aberrant expression of B-cell marker CD79a is noted. This feature supports a diagnosis of acute myeloid leukemia.

			H gate Dim CD45+ 	A gate Bright CD45+
   Total events         events = 10936          events = 2522
   analyzed = 26181    (42% of total)	       (10% of total)
     
  CD45+/CD14-		     99%		     99%
  Total CD13+		     67%
  CD34+/CD13+		     63%
  Total CD15+		     25%
  CD34+/CD15+		     24%
  Total CD33+		     96%
  CD34+/CD33+		     90%
  Total CD34+		     93%
  CD11b+		     82%
  Total CD41+		     <2%
  CD34+/CD71+		     89%
  CD34+/CD117+		     92%
  Total HLA DR+		      2%
  CD34+/HLA DR+		      2%
  cCD3+			      4%
  cCD79a+		     61%
  cMPO+			     13%

Specimen: Bone marrow aspirate.

An aberrant population of cells expressing CD34, CD117, CD33, CD13 (partial), CD38,and CD11b is identified at 76% of the total events analyzed. The aberrant cells are negative for HLA-DR and CD15. The immunophenotype is consistent with acute myeloid leukemia.
 

 Total events  H gate Dim CD45+   A gate Bright
 analyzed= 50688    events= 36033      CD45+ events = 3028
                    (76% of total)    (6% of total)

  CD45+/CD14- 99% 95%
  Total CD14+ <2%
  Total CD13+ 30%
  CD34+/CD13+ 29%
  Total CD15+ 4%
  CD34+/CD15+ 4%
  Total CD33+ 99%
  CD34+/CD33+ 98%
  Total CD34+ 99%
  CD11b+ 73%
  Total CD41+ 7%
  CD34+/CD71+ 97%
  CD34+/CD117+ 97%
  Total HLA DR+ 6%
  CD34+/HLA DR+ 6%
  Total CD19+ <2%         7%
  CD19+/CD20+ <2%   7%
  Total CD38+ 98% 94%
  CD19+/CD38+ <2%   7%
  CD19+/CD10+ <2% <2%

CYTOGENETICS (UNMC, Cytogenetics)

IMMUNOHISTOCHEMISTRY STAINS

DIAGNOSIS

Acute myeloid leukemia