Question 119
A 62-year-old male is scheduled for an elective cholecystectomy. Routine laboratory testing prior to the surgery reveals a hemoglobin concentration of 19.5 g/dL. Physical examination reveals an enlarged liver and an enlarged spleen. Additional laboratory testing reveals a low concentration of erythropoietin. Of the following, which is the most likely diagnosis?
A. Chronic myelogenous leukemia
B. Hairy cell leukemia
C. Epstein-Barr virus infection
D. Polycythemia rubra vera
E. Occult renal cell carcinoma
Answer for Question 119
Answer: D (Polycythemia rubra vera)
Explanation: Polycythemia rubra vera is often asymptomatic and thus could be identified during routine laboratory testing prior to surgery. Patients have an elevated hemoglobin and a low to normal erythropoietin concentration. Hepatomegaly and splenomegaly are common findings on physical examination. Renal cell carcinoma can produce erythropoietin, and thus, cause an elevated hemoglobin concentration. Chronic myelogenous leukemia, hairy cell leukemia, and EBV infection are also associated with splenomegaly, but are not causes of primary polycythemia.
Question 120
A 61-year-old male presents to his family physician. Over the past six months, he has had numerous episodes of weakness, lightheadedness, and headache, and occasionally dyspnea when he is working at his ranch. He also notes that after a bath his skin is particularly itchy. Laboratory testing reveals a hemoglobin of 20.2 g/dL. Genetic testing would most likely reveal which of the following?
A. JAK2 mutation
B. PAK2 mutation
C. RB mutation
D. p53 mutation
E. t(15;17)
F. t(9;22)
G. t(8;21)
H. inv 16
Answer for Question 120
Answer: A (JAK2 mutation)
Explanation: The clinical scenario is consistent with polycythemia rubra vera, which occurs in patients around the age of 60 years, and, while it can be asymptomatic, it can also cause weakness, fatigue, lightheadedness, and dyspnea. Male patients will have a hemoglobin of >18.5 g/dL. A mutation of JAK2, commonly V617F, is present in almost all patients with polycythemia rubra vera.
Question 121
A 53-year-old male presents to his family physician with complaints of fatigue that has developed over the past 6 months. Physical examination reveals normal lung and heart sounds. Palpation of the abdomen reveals an enlarged spleen. Laboratory testing reveals a white blood cell count of 45,000/μL. The platelet count is normal and the hemoglobin is 11.1 g/dL. A peripheral smear of the blood reveals an increased number of both mature and immature white blood cells as well as an increased number of basophils. Genetic analysis would reveal which of the following?
A. t(8;21)
B. t(15;17)
C. t(9;22)
D. t(8;14)
E. t(8;22)
Answer for Question 121
Answer: C (t(9;22)
Explanation: The clinical scenario is consistent with chronic myelogenous leukemia (CML), which most commonly presents in individuals aged 45-55 years of age, and may be asymptomatic or present with non-specific symptoms early on. The white blood cell count is elevated, and in CML, an increased number of basophils is characteristic. Splenomegaly is a common physical finding. The translocation associated with CML is t(9;22). t(8;21) and t(15:17) are associated with AML, and patients would present more precipitously and the increased white blood cell count would be dominated by blasts. t(8;14) and t(8;22) are characteristic of Burkitt lymphoma, which presents in children and young adults, and would present most commonly as a mass lesion and not a leukemia.