White Blood Cell Case Studies


CASE 4: Acute Myelogenous Leukemia


Clinical History:

A 30-year-old man has noted progressive weakness over the past month. On physical examination he has a few small non-tender lymph nodes palpable in both axillae, and the tip of his spleen is palpable. There is also sternal tenderness present on palpation, but no mass lesion or overlying skin changes. Laboratory studies include a CBC that shows Hgb 10.2 g/dl, Hct 30.5%, MCV 88 fL, platelet count 36,000/microliter, and WBC count 67,000/microliter. His peripheral blood smear is shown:
  1. What is the prominent white blood cell type seen on this smear?

    2. Most of the WBC's in this peripheral smear are myeloblasts. Except for occasional mature neutrophils on the smear, intervening stages of maturing neutrophils are not seen. Some nucleated red blood cells are also present in other areas not pictured. Platelets are reduced in number and some large forms are seen.

  2. Do you see any intracytoplasmic markers which are diagnostic in this case?

    3. A diagnostic marker is the presence of slender red, needle-like bodies in the cytoplasm of the myeloblasts called Auer rods.

  3. What is your diagnosis?

    4. The diagnosis is acute myeloblastic leukemia (AML). Most patients with acute leukemia have a markedly decreased platelet count. A peroxidase or Sudan black stain will identify the blasts as being of granulocytic series. The leukemic cells interfere with normal hematopoiesis. When a bone marrow and smear are performed, it is seen that, instead of some adipocytes (the cellular composition of the marrow in the posterior iliac crest in this patient should be at least 50% hematopoietic elements) the marrow is nearly 100% cellular, and normal erythroid, myeloid, and megakaryocytic cells lines are replaced by leukemic blasts. Thus, patients with leukemia can have anemia, leukopenia (of normal WBCs), and thrombocytopenia, or all three (pancytopenia). AML can be further sub-classified on the basis of cellular and cytochemical properties.

  4. What do you tell the patient about his chances with a bone marrow transplant?

    5. Once he is told the risks and benefits of a bone marrow transplant (BMT), he will have a very difficulty decision to make. Of course, if the disease has an 80-90% chance of 5 year remission, it should be a pretty easy decision, but if there is only a 10-25% chance of survival, even for 5 years, it really should not be an easy decision. After all, without the BMT there might be a good six months followed by a sick six months. But with the BMT there could be a sick six months ending with death, without getting to enjoy the good six months.

    The truth is, there are few treatments that we put patients through that are worse than BMT. Just think about the period after the immune system is destroyed with total body radiation and highly toxic chemotherapy. After infusing the new stem cells, the health care team and the patient and the family are all anxious to see if engraftment occurs. This could take days, which will seem like an eternity. But it could take weeks, and each day knowing things are looking bleaker. The outlook worsens with a major complication, such as a life-threatening infection. And if engraftment doesn't occur, what can you do? It's too late even for hospice.