Labs

What is your next step to work-up this patient?

a
Urgent ID consult
b
Urgent Heme-Onc consult
c
CBC and differential
His presentation is concerning for a hematologic malignancy given the presence of B symptoms (systemic symptoms including fatigue, fever, night sweats, weight loss). Additionally, he has further evidence of anemia given his fatigue and conjunctival pallor, further evidence of thrombocytopenia given his easy bruising and epistaxis, and evidence of a leukocyte abnormality given his fever and signs of infection. While all the above may be needed at some point, the first step to evaluate this possible hematologic malignancy is a CBC with differential.
d
Bone marrow biopsy

The following is the patient’s CBC:

(Please fill in RDW-SD)

WBC (109/L)Hb (g/dL)Hct (%)MCV (fL)RDW-SD (fL)PLT (109/L)
1.44.614.9107XX21

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 fL, platelets (PLT) 150-450 x 109/L

The white cell differential showed (THE NUMBERS TO NOT ADD UP TO THE INITIAL WBC – THEY NEED TO BE ADJUSTED):

  • Absolute neutrophil count      0.50
  • Absolute lymphocyte count    0.18
  • Absolute monocyte count       0.01
  • Absolute eosinophil count      0.01
  • Absolute basophil count         0.01

Notice that we have provided you with the absolute counts and not the percentages of the various white blood cell subtypes. That’s because the definition of cytopenias and cytoses for the 5 major white cell types is based on absolute counts! And to determine what these values mean, we can refer to our cheat sheet:

Together with the history and physical exam, which of the following lab abnormalities defines this patient’s clinical presentation as a medical emergency (choose one)?

a
Anemia
b
Neutropenia
As suspected, his labs show pancytopenia and are concerning for a hematologic malignancy. We now see he is neutropenic, and given that he also has a fever we can diagnose him with febrile neutropenia which is a medical emergency. He will additionally require an urgent red blood cell transfusion, and potentially a platelet transfusion later in his course.
c
Thrombocytopenia

True of false: all patients with pancytopenia should be admitted to the hospital.

a
True
b
False
It is important to know that pancytopenia itself is not often an indication for admission and is frequently treated on an outpatient basis. However, given febrile neutropenia and severe anemia, this patient was started on broad spectrum antibiotics and admitted for prompt workup and management.

You order a number of other blood tests, including a peripheral smear (which we will look at shortly), a metabolic panel, liver function tests and LDH. All of these results are normally (TRUE FOR LDH)? You next obtain an abdominal CT scan, which is shown next:

As you can see, the patient’s imaging shows massive splenomegaly. Massive splenomegaly is not precisely defined radiologically. Most authors define massive splenomegaly when the spleen is clinically palpable > 8 cm below left costal margin, reaches the iliac crest, crosses the midline or weighs more than 1500 g. 

What is the most likely mechanism of splenomegaly in this patient?

a
Congestion
b
Work hypertrophy
c
Infiltrative
While we do not yet know this patient’s specific diagnosis, it is highly concerning for a hematologic malignancy. The mechanism of splenomegaly in most hematologic malignancies is infiltration by neoplastic cells.

Let’s look at the peripheral smear:

We have a clinical suspicion of hairy cell leukemia. You preform a bone marrow examination. You notice that the tap is “dry”. Flow cytometry returns and is remarkable for (BUT THE TAP WAS DRY, HOW DID YOU GET MATERIAL FOR FLOW? Peripheral blood?):

  • CD19 Positive
  • CD20 Positive
  • Kappa light chain restricted
  • CD5 Negative
  • CD10 Negative
  • CD11c Positive
  • CD25 Positive
  • CD103 Positive

These flow cytometry results are consistent with a diagnosis of hairy cell leukemia. Blood or bone marrow aspirate (BMA) flow cytometry typically shows strong expression of CD22, CD20, and CD11c, and positive CD25, CD19, CD103, and CD123.

The final diagnostic test you performed is a next-generation sequencing panel of lymphoid associated genes. What mutation/translocation do you expect to see?

a
Translocation 15;17
Translocation 15;17 is the mutation found in APML.
b
BRAF p.V600E mutation
The BRAF p.V600E mutation is present in nearly 100% of patients with classical hairy cell leukemia. The variant type of HCL will have a MAP2K1 mutation 30% of the time.
c
MAP2K1 mutation
d
Deletion 13q14
Deletion 13q14 is the most common mutation found in CLL (50-60% prevalence) .
e
MYD88 mutation
MYD88 mutations are found in most cases of Waldenstrom’s Macroglobulinemia.

Where does hairy cell leukemia fit in the overall scheme of leukemia?

a
It is a type of myeloid leukemia
b
It is a type of lymphoid leukemia
c
It is a mature B-cell neoplasm
d
It is a mature T-cell neoplasm
e
It is a type of acute leukemia
Prev
 1 / 11 
Next