Let’s begin with the patient’s complete blood count (CBC) at the time of admission:

8.65.415.7101 34.453.515

What’s what: WBC, white blood cell count; Hb, hemoglobin; MCV, mean cell volume; MCHC, mean cellular hemoglobin concentration; RDW-SD, red cell distribution width-standard deviation; platelets, PLT; Normal values: WBC 5-10 x 109/L, RBC 4-6 x 1012/L, Hb 12-16 g/dL, Hct 35-47%, MCV 80-100 fL, MCHC 32-36 g/dL, RDW-SD < 45%, platelets (PLT) 150-450 x 109/L

True or false: given that her total white blood cell (WBC) count is normal, there is no need to obtain a WBC differential (i.e., we can assume it will be normal).

Correct! There are many permutations of abnormal white cell subset counts that may occur in the context a normal total white cell count.

Here is the white blood cell differential:

Here is the peripheral blood smear:

A number of other blood tests were performed but let’s jump to the bone marrow examination (next slide).

Here is the bone marrow aspirate:

Food for thought (we will return to these questions):

  • What is your differential diagnosis?
  • Can you make a definitive nosological diagnosis from examination of the marrow smear alone?
  • What other tests would you order?

Because of the severity of SOB a chest CT was obtained.

Results of BAL:

[Ask user to describe or simply have German describe]

Final diagnosis:

  • Acute myeloid leukemia with inv(16)(p13;q22) and CBFB/MYH11 [German, we may want to include a slide about testing with FISH/cytogenetics before giving away diagnosis]
  • Pulmonary leukostasis

Key observation: abnormal eo-baso precursors with cytoplasmic granules two to three times bigger than normal + blast (number of blasts or eo-baso precursors does not matter)

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