This page is dedicated to organizing various examples of standardized exam questions whose answer is chronic myelogenous leukemia (CML). While this may seem a odd practice, it is useful to see multiple examples of how CML will be characterized on standardized exams (namely the boards and the shelf exams). This page is not meant to be used as a traditional question bank (as all of the answers will be the same), however seeing the classic “test” characterization for a disease is quite valuable.
KEY CHARACTERISTICS OF THIS CONDITION (ON EXAMS)
When it comes to standardized exams, each topic has its own “code” marked by key buzzwords, lab findings, clues, etc. If you are well versed in this code you will be able to more quickly identify the condition that is being discussed, and get the right answer on the exam you are taking. Below is the “code” for CML.
- Elevated white count: not specific to CML, but will be present in patients who have a CBC.
- Thrombocytosis (elevated platelet counts) can be seen in roughly half of patients (unique to CML, other leukemias will present with only thrombocytopenia).
- Thrombocytopenia is also of course possible so do not assume because a patient has low platelets they DON’T have CML.
- Low leukocyte alkaline phosphatase levels: this is a finding very specific to CML.
Question # 1
70-year-old woman comes to the clinic because she has been feeling progressively fatigued has not been able to eat regularly for the last six months. She has lost 5 pounds in this time and she explains that she gets full easily. She denies having any abdominal pain, night sweats, or fevers. The patient’s past medical history is remarkable for hypothyroidism, hypertension, and gout. She denies using any tobacco, alcohol, or illicit drugs. Her temperature is 99.8 F, blood pressure is 130/80 mm Hg, and heart rate is 85/min. Physical exam is remarkable for mild mucosal pallor, and a spleen tip that is felt with deep palpation. Lab results are as follows:
- Hemoglobin: 8.3 g/dL
- Platelets: 185,000/mm³
- Leukocytes: 43,000/mm³
Fluorescent in situ hybridization reveals an abnormality on chromosome 22. What is the likely diagnosis in this patient?
Explanation # 1
Abnormality of chromo 22 (seen on FISH) = CML
Question # 2
A 50 year old male comes to the clinic because he has been suffering from a week of purulent nasal discharge, sore throat, a cough, and a headache. His past medical history is unremarkable, other then a history of infectious mononucleosis when he was a teenager. The patient has a 15 pack year history of smoking, but does not drink alcohol. His current temperature is 100.6°F. His maxillary sinuses are tender, his pharynx is erythematous, and lymph nodes are palpable along the anterior cervical chain. The patient has labs collected which are shown below:
- Neutrophils: 38%
- Myelocytes: 32%***
- Metamyelocytes: 8%
- Band forms: 1%
- Blast cells: 1%
- Eosinophils: 7%
- Basophils: 5%
The patient’s leukocyte alkaline phosphatase score is low compared to reference ranges. What is the likely diagnosis?
Explanation # 2
Elevated white count + large amount of myelocytes (inmature) + low leukocyte alkaline phosphatase score = CML
Question # 3
A 55 year old male comes to the clinic because he has been dealing with malaise and fatigue for the past 3 months. He explains that he has also had a 25 lb weigh tloss during this period of time, which has him quite concerned. A physical exam revels that the patent has no abdominal tenderness, but does have splenomegaly. His WBC count is currently 80,000/mm³. A bone marrow biopsy is performed, and reveals a specimen with hypercellularity and maturing granulocytes. The biopsy also contains large numbers of megakaryocytes as well, and normal erythroid elements. What is a possible diagnosis in this patient?
Explanation # 3
Elevated white count + bone marrow showing many cells (that are granulocytes) + large amount of megakaryocytes in biopsy as well (implies thrombocytopenia) = CML
Question # 4
A 6o year old man comes to the clinic because he has a 15 day history of fatigue, cough, and shortness of breath. Currently he is not in any respiratory distress, and his lungs are clear to auscultation. Labs are collected and shown below:
- Hemoglobin: 10.9g/dL
- WBC: 140,00/mm³
- Platelet count: 850,00/mm³
What is the likely diagnosis in this patient?
Explanation # 4
Very elevated WBC count + very elevated platelets = CML
Question # 5
A 40 year old man comes to the clinic because he has been suffering form a 20 lb weight loss for the past 4 months. He says that the weight loss is not intentional, and that he has tried to maintain his normal diet, but that he gets full more quickly these days. His past medical history is unremarkable and he takes no chronic medications. Vital signs are all within reference ranges. His abodminal exam reveals splenomegaly. Labs are conducted and shown below:
- Hematocrit: 43%
- WBC: 25,000/mm³ ***
- Segmented neutrophils: 45%
- Bands: 10%
- Myelocytes: 15% ***
- Metamyelocytes: 5% ***
- Basophils: 4%
- Eosinophils: 3%
- Lymphocytes: 13%
- Platelets: 575,000/mm³ ***
What is the likely diagnosis in this patient?
Explanation # 5
Elevated white count + large amount of myelocytes (inmature) + large amount of metamyelocytes + elevated platelets = CML
Question # 6
A 65 year old male complains of bone pain and fatigue for the past 3 months. A physical exam shows a palpable spleen tip that is 3 cm below the costal margin. Labs are collected and shown below:
- Hemoglobin: 13.9 g/dL
- WBC: 27,300/mm³ ***
- Platelet count: 695,000/mm³ ***
Leukocyte alkaline phosphatase activity is assayed and is shown to be decreased in the patient. What is the likely diagnosis?
Explanation # 6
Elevated white count + large amount of platelets + low leukocyte alkaline phosphatase score = CML
TESTABLE FACTS ABOUT THIS TOPIC (BEYOND ITS IDENTIFICATION)
Many questions on standardized exams go beyond simply recognizing the underlying topic. Often there are specific testable facts regarding some aspect of the topic’s pathophysiology/management/clinical implications that are commonly asked. Some of these are listed below:
- Philadelphia chromosome: translocation between chromosomes 9 and 22.
- BCR/ABL fusion protein: is the byproduct of the translation and is oncogenic
- Imatinib: this is a ABL kinase inhibitor.
Page Updated: 02.07.2017