Case study:

History:

• 15 year old male.
• Flu-like symptoms with a severe sore throat for two weeks prior to admission.

Physical Exam:

• Cervical and axillary adenopathy.
• No other organomegaly.

­ CBC (with microscopic differential):

RBC               3.15 x 10¹²/L      (4.5-5.3 × 10¹²/L)

HGB               9.9  g/Dl           (13-16 g/dL)

HCT              28.5  %              (36-51 %)

MCV              90.5  fL             (79-98 fL)

MCH              31.4  pg             (25-35 pg)

MCHC             34.7  g/dL           (32-36 g/dL)

RDW              15.2  %              (11.5 – 14.0 %)

WBC              42.6  x 10⁹/L         (4.5-13.0 x 10⁹/L)

Lym               12  %             (25-45 %)

abnormal cells  88  %             (0 %)

(see Picture)

PLT              22   x 10⁹/L          (150-450 x 10⁹/L)

Further Laboratory Studies:

Bone marrow biopsy:

Aspirate: The differential showed 100% cells similar to those seen in the blood.

Sections: Markedly hypercellular.

Cytochemistry:

Myeloperoxidase        negative

Sudan black B              negative

Non-specific esterase              positive

Immunophenotyping:

Not done.

Chemistry:

Serum lysozyme         162 mg/L        (RI 4-13)

Please answer the following questions:

1. What morphologic alterations are seen in this blood smear field? (Please comment on the white blood cells and on the red blood cells seen in the picture.)

(6 Marks)

2. What is the most likely diagnosis given the information given above?

(1 Mark)

3. How do the ‘further laboratory studies’ aid with determining the diagnosis? (Please comment briefly on each test).

(4 Marks)

4. Immunophenotyping was not performed. How could immunophenotyping have helped with the diagnosis? Name two CD markers that are likely expressed on the pictured WBC.

(4 Marks)