February, 2020 | Pathology Review for USMLE

Questions 159-161: Lung pathology

Question 159

A 32-year-old male presents to an acute care clinic with complaints of chest pain that is worse when he breathes in. The chest pain started about a day ago. A few hours ago he coughed up blood. Physical examination reveals some dullness to percussion in the left upper lobe and crackles are heard at that site. His only past medical history is that he broke his left tibia one week ago while skiing, and has had to wear a cast, which he reports has hindered his ability to get around like normal. Of the following, which laboratory test is most likely to be elevated?

A. D-Dimer
B. PTT
C. AST
D. Hct
E. Glucose

Answer for Question 159

Answer: A (D-dimer)

Explanation: The clinical scenario is consistent with a pulmonary thromboembolus, which can present with pleuritic chest pain and hemoptysis. A peripheral thromboembolus can produce an infarction of the lung, which would lead to the dullness to percussion and crackles. The immobility is a risk factor for deep venous thrombosis and resultant pulmonary thromboembolus. Of the laboratory tests listed, an elevated d-dimer is most associated with deep venous thrombi and a pulmonary thromboembolus. In a patient with anti-phospholipid antibody syndrome, an elevated PTT would be possible, and those patients are at risk for thrombi and embolism; however, the history does not otherwise suggest this condition, and it is only one of many conditions that could possibly predipose to thrombosis and embolism.

Question 160

A 23-year-old tall and thin male presents to the emergency room at 2 am, saying that he awoke due to a sudden pain in his chest that was worse when he breathed, and has had difficulty breathing since that time. Physical examination reveals hyperresonance to percussion on the left side of his chest, which is associated with decreased breath sounds and absence of tactile fremitus. Of the following, what is the most likely diagnosis?

A. Acute myocardial infarct
B. Aortic dissection associated with Marfan syndrome
C. Pneumothorax
D. Lobar pneumonia
E. Pulmonary thromboembolus

Answer for Question 160

Answer: C (Pneumothorax)

Explanation: The clinical presentation is classic for a spontaneous pneumothorax (tall thin young male with sudden onset pleuritic chest pain and dyspnea). Physical examination is likewise consistent with pneumothorax – the hyperresonance occurs because the pleural cavity is filled with air, as do the decreased breath sounds and absence of tactile fremitus, since the lung is displaced away from the chest wall by intervening air. Although tall and thin suggest Marfan syndrome, the physical examination is not consistent with an aortic dissection and hemothorax (especially the hyperresonance); also, the patient would be potentially in shock from blood loss if an aortic dissection were the cause of his symptoms. The physical examination is also not consistent with pulmonary thromboembolus, although the sudden onset of dyspnea and pleuritic chest pain could be consistent.

Question 161

A 16-year-old tall male is playing basketball with friends when he suddenly develops chest pain and shortness of breath. His friends take him to the emergency room where a physical examination reveals hyperresonance to percussion on the left side of his chest, which is associated with decreased breath sounds and absence of tactile fremitus. Of the following, what is the most likely underlying pathologic finding?

A. Ruptured pulmonary bleb
B. Inflammation of blood vessel
C. Tearing of large caliber blood vessel
D. Asymmetric thickening of myocardium
E. Thrombus in blood vessel

Answer for Question 161

Answer: A (Ruptured pulmonary bleb)

Explanation: The clinical presentation is classic for a spontaneous pneumothorax (tall young male with sudden onset chest pain and dyspnea). Physical examination is likewise consistent with pneumothorax – the hyperresonance occurs because the pleural cavity is filled with air, and the decreased breath sounds and absence of tactile fremitus, since the lung is displaced away from the chest wall by intervening air. Although tall and thin suggest Marfan syndrome, the physical examination is not consistent with an aortic dissection and hemothorax (especially the hyperresonance), and thus a tearing of large caliber blood vessel is not the finding; also, the patient would be potentially in shock from blood loss. Although patients with hypertrophic cardiomyopathy can present as sudden death, the history and physical examination findings are not consistent with the diagnosis (i.e., a patient with hypertrophic cardiomyopathy would not normally developed sudden chest pain and shortness of breath). The physical examination findings are not consistent with a vasculitis or pulmonary thromboembolus.

Questions 156-158: Lung pathology

Question 156

A 29-year-old male presents to an acute care clinic with complaints of a productive cough and fever to 38.7 degrees Celsius for the past 3 days, associated with some chest pain when he breaths and with chills. Physical examination reveals dullness to percussion on the left side of the chest. Crackles and a pleural rub are also heard at this location. A chest x-ray reveals consolidation of the left lung. A sputum culture is obtained and grows a pure sample of gram positive cocci in chains. Of the following, laboratory testing of this organism would reveal which of the following traits?

A. Not inhibited by optochin
B. Beta hemolytic
C. Bile soluble
D. Non-fermenter of glucose
E. Catalase positive

Answer for Question 156

Answer: C (Bile soluble)

Explanation: The presenting features are consistent with a community acquired pneumonia, consistent with a lobar pneumonia. A common cause of a lobar pneumonia is Streptococcus pneumoniae, which is gram positive and grows in chains. Streptococcus pneumoniae is bile soluble. It is also inhibited by optochin, alpha hemolytic, a fermenter of glucose, and catalase negative.

Question 157

Following a four day illness that was characterized by a high fever (up to 41 degrees Celsius) and severe muscle aches, a 29-year-old male presents to the emergency room with complaints of dyspnea with exertion, chest pain which is worse with expiration, and a productive cough. Physical examination reveals dullness to percussion on the left side of the chest. Crackles and a pleural rub are also heard at this location. A chest x-ray reveals consolidation of the left lung. A sputum culture is obtained and grows a pure sample of gram positive cocci in clusters. Of the following, laboratory testing of this organism would reveal which of the following traits?

A. Catalase negative
B. Coagulase positive
C. Alpha hemolysis
D. Non-fermenter of glucose

Answer for Question 157

Answer: B (Coagulase positive)

Explanation: The preceding illness has features of influenza (high fever and myalgias). One complication of influenza is the subsequent development of a secondary bacterial infection. In this situation, the patient developed Staphylococcus aureus, which is a common etiologic agent of a secondary bacterial infection in patients with influenza. Staphylococcus aureus is coagulase positive. It is also catalase positive, beta hemolytic and a fermenter of glucose.

Question 158

A 73-year-old male with the history of a stroke 2 years ago that left him with residual motor difficulties in eating is brought to the emergency room by his family because over the past three weeks he had developed a productive cough with foul-smelling sputum. In addition, he has lost about 10 lb. and has an intermittent fever (although his temperature wasn’t taken). He has no history of tobacco use. A chest x-ray reveals an infiltrate in the lower lobe of the right lung. Of the following, what is the most likely diagnosis?

A. Community acquired bacterial pneumonia
B. Community acquired viral pneumonia
C. Aspiration pneumonia
D. Mycobacterium tuberculosis
E. Necrotic pulmonary neoplasm

Answer for Question 158

Answer: C (Aspiration pneumonia)

Explanation: Elderly individuals, especially those with a history of a condition that would cause neuromuscular impairment, such as a stroke, are at risk for aspiration pneumonia. Because aspiration pneumonia often involves anaerobic bacteria and/or abscess formation, the patient can produce foul-smelling sputum. With aspiration pneumonia, patients often present over weeks or months and can have fever and weight loss. The lower lobes are affected, and more often the right side than the left side as the angle of the right bronchus allows for aspirated material to more easily enter the right lung.

Questions 153-155: Lung pathology

Question 153

A 29-year-old female presents to an acute care clinic with complaints of a productive cough and fever to 38.6 degrees Celsius for the past 4 days. Physical examination reveals dullness to percussion on the lower left side of the chest and crackles are heard at this location. A chest x-ray reveals consolidation of the lower lobe of the left lung. A sputum culture grows Streptococcus pneumoniae. Of the following, which is the most responsible for the physical examination findings?

A. Collapse of alveoli
B. Proteinaceous exudate on alveolar septae
C. Bacterial overgrowth
D. Lymphocytic infiltration of alveolar septae
E. Neutrophilic infiltration of alveolar airspaces

Answer for Question 153

Answer: E (Neutrophilic infiltration of alveolar airspaces)

Explanation: The presenting symptoms are consistent with a community-acquired pneumonia, and the physical examination and chest x-ray are consistent with a lobar pneumonia, which is most commonly caused by Streptococcus pneumoniae. Although atelectasis, hyaline membranes, and bacterial overgrowth could/would all be present to some degree, the cause for the consolidation of the lung tissue (i.e., the lung tissue having a more solid appearance) is due to the neutrophilic infiltrate in the alveolar airspaces, filling the airspaces in the lung. Lymphocytic infiltration of the alveolar septae would be characteristic of a viral infection.

Question 154

A 34-year-old male presents to an acute care clinic with complaints of a productive cough and fever to 38.4 degrees Celsius for the past 3 days, associated with shaking chills and some chest pain when he breaths. Physical examination reveals dullness to percussion on the left side of the chest. Crackles and a pleural rub are also heard at this location. A chest x-ray reveals consolidation of the left lung. Of the following, if untreated, which complication is he most likely to develop?

A. Bronchogenic carcinoma
B. Amyloidosis
C. Fibrosis in the left pleural cavity
D. Alzheimer disease
E. Aortic dissection

Answer for Question 154

Answer: C (Fibrosis in the left pleural cavity)

Explanation: Given the clinical presentation, a bacterial lobar pneumonia is likely. The pleural friction rub would indicate that there is pleuritis. With a bacterial infection causing pleuritis, complete resolution would be less likely, and scar formation would occur. Bacterial (and viral) pneumonias are not a significant risk factor for the other disease processes listed.

Question 155

A 26-year-old male presents to the hospital with complaints of difficulty breathing, which has severely worsened over the past day. In the five days prior, he has had a fever, productive cough, and chills. In addition, his chest has hurt when he breathed in and with exertion he was short of breath. His friends told him to come to the emergency room two days ago, but he thought that he could wait it out. He has a temperature of 101 degrees Fahrenheit, heart rate of 108 bpm, blood pressure of 105/71 mmHg, and respiratory rate of 28 breaths per minute. Physical examination reveals dullness to percussion on the left side of the chest, accompanied by decreased breath sounds, and an absence of tactile fremitus. Of the following, what is the most likely diagnosis?

A. Pulmonary thromboembolus
B. Congestive heart failure associated with bicuspid aortic valve
C. Tension pneumothorax due to ruptured bleb
D. Empyema
E. Aspiration pneumonia with abscess formation

Answer for Question 155

Answer: D (Empyema)

Explanation: The clinical presentation is consistent with a community acquired pneumonia. The dullness to percussion on the left side of the chest combined with the decreased breath sounds and absence of tactile fremitus are consistent with an empyema. While the pneumonia alone could cause the dullness to percussion associated with the consolidation of the lobe, there would not be decreased breath sounds, and there would be tactile fremitus. While a pulmonary thromboembolus could, with infarction, lead to dullness to percussion, it would not produce the other physical examination findings, and is not associated with a productive cough. Congestive heart failure due to a bicuspid aortic valve would present much later in life, and would not be associated with the productive cough The individual has no described risk factors for aspiration pneumonia.

Questions 150-152: Lung pathology

Question 150

A 27-year-old male, who is a college instructor, presents to an acute care clinic with complaints of a productive cough for 3 days, a fever, and occasional difficulty breathing with exertion. He has no significant past medical history and does not smoke. A chest x-ray reveals consolidation of the lower lobe of the right lung. Of the following, what is the most likely etiology for his clinical presentation?

A. Bacterial infection
B. Parasitic infection
C. Mycobacterial infection
D. Aspiration
E. Neoplasm

Answer for Question 150

Answer: A (Bacterial infection)

Explanation: The presentation (short duration of productive cough, fever, and dyspnea) in an individual with no past medical history and with consolidation of one lung lobe is consistent with a lobar pneumonia, which, in this situation, would be a community-acquired bacterial infection, or possibly a community acquired viral infection, which can also have consolidation of a lung lobe on x-ray. Lobar pneumonia is often bacterial in origin, and most commonly Streptococcus pneumoniae. Given his history, Mycobacterium tuberculosis is unlikely (i.e., he is not homeless, or otherwise living under conditions likely to expose him to tuberculosis). He has no risk factor for aspiration; and given his young age and lack of smoking history, a pulmonary neoplasm would be very unlikely.

Question 151

A 33-year-old female, who is a nurse at the hospital, presents to an acute care clinic with complaints of a productive cough for 2 days associated with shaking chills. She also reports a fever of 38.5 degrees Celsius. She has no significant past medical history and does not smoke. Her heart rate is 105 bpm, her respiratory rate is 26 breaths per minute, and her blood pressure is 82/61 mmHg, which is lower than normal for her. A chest x-ray reveals consolidation of the lower lobe of the left lung. A blood culture is positive. Of the following, which condition in her past medical history would represent the most important risk factor for her current presenting condition?

A. Fracture of the left tibia three years ago while skiing
B. Remote splenectomy after abdominal trauma
C. Head injury following rock climbing fall
D. Past episode of deep venous thrombosis
E. History of acute rheumatic fever

Answer for Question 151

Answer: B (Remote splenectomy after abdominal trauma)

Explanation: The presenting features (productive cough and fever) combined with the x-ray results are consistent with a community-acquired pneumonia, which would likely be a lobar pneumonia in this case. The most common bacterial etiologic agent for a lobar pneumonia is Streptococcus pneumoniae. Individuals without a spleen are at increased risk for the development of a pneumococcal sepsis as the spleen plays a role in the production of antibodies against polysaccharides, which protect against encapsulated organisms. The other conditions would be play a significant role in her development of pneumonia or resultant sepsis.

Question 152

A 24-year-old male who has smoked since he was 14 years old but has no other past medical history presents to an acute care clinic in July with complaints of a productive cough and fever to 38.4 degrees Celsius for the past 4 days. Physical examination reveals dullness to percussion on the lower left side of the chest and crackles are heard at this location. Of the following, what is the most likely diagnosis?

A. Community-acquired pneumonia
B. Chronic bronchitis
C. Pulmonary thromboembolus
D. Bronchogenic carcinoma
E. Aspiration pneumonia

Answer for Question 152

Answer: A (Community-acquired pneumonia)

Explanation: The presentation (cough and fever) and physical examination (dullness to percussion and crackles) are consistent with a community-acquired pneumonia. While chronic bronchitis can present with a productive cough, patients would normally be afebrile and there would be no localizing physical examination findings (i.e., the dullness to percussion or crackles). While a pulmonary thromboembolus could, with infarction, lead to a region of dullness to percussion and crackles, and could have a fever, the productive cough would not be typical and the patient has no risk factors for deep venous thrombi. Even though he has a smoking history, a bronchogenic carcinoma would be rare at this age. While aspiration pneumonia could cause the signs and symptoms listed, the patient has no risk factors for aspiration (e.g., a neuromuscular disease, or drug/alcohol intoxication).

Question 149: Hematopathology

Question 149

While on a 4th year elective rotation in Africa, a medical student sees a 1-year-old black female who was brought to the clinic by her parents. Physical examination reveals prominence of the malar eminences of the cranium, yellow-tinged conjunctivae, ulcers of the skin of the legs, an incorrectly healed fracture of the left leg, and massive splenomegaly. A peripheral smear reveals marked variation in the size and shape of the red blood cells, and nucleated red blood cells are present. Of the following, what is the most likely diagnosis?

A. Sickle cell anemia
B. β-thalassemia
C. Child abuse
D. Severe chronic malaria
E. Acute lymphoblastic leukemia
F. Acute and chronic cholecystitis

Answer for Question 149

Answer: B (β-thalassemia)

Explanation: In β-thalassemia major, the ineffective erythropoeisis leads to expansion of the marrow cavity, and hence the prominence of the malar eminences. Involvement of the long bones can predispose to fractures. The hemolysis associated with the ineffective erythropoeisis leads to an elevated concentrated of unconjugated bilirubin and can manifest as jaundice. And, while the unconjugated bilirubin can predispose to cholelithiasis, acute and chronic cholecystitis is not the sole cause of this child’s condition. On blood smear, β-thalassemia major has poikilocytosis (variation in cell shape) and anisocytosis (variation in cell size).

Questions 146-148: Hematopathology

Question 146

A 44-year-old male with a history of alcohol use presents to his family physician with complaints of fatigue. Physical examination reveals an enlarged liver, but is otherwise unremarkable. Laboratory testing reveals:

Hemoglobin: 9.2 g/dL
Hematocrit: 27%
White blood cell count: 10.2 x 103 cells/mm3
Mean corpuscular volume: 107 fL
Platelet count: 300,000/mm3

Total bilirubin: 0.6 mg/dL
Direct: 0.2 mg/dL
Alkaline phosphatase: 142 U/L
AST: 245 U/L
ALT: 137 U/L
Gamma-glutamyltransferase: 250 U/L
Albumin: 2.8 g/dL

A peripheral smear of the blood is performed. Of the following red blood cell morphologies, which is most likely to be present?

A. Tear drop cells
B. Howell-Jolly bodies
C. Schistocytes
D. Burr cells
E. Reticulocytes

Answer for Question 146

Answer: D (Burr cells)

Explanation: The patient has liver disease, most likely related to his alcohol abuse, which is suggested by the history and the AST/ALT ratio. The patient also has an anemia, which is most likely due to decreased production, and therefore, reticulocytes are not likely to be present. Burr cells (and spur cells) are associated with liver disease. Target cells are associated with obstructive liver disease. Howell-Jolly bodies occur post-splenectomy or in patients with hyposplenism (e.g., sickle cell patients).

Question 147

A 24-year-old Asian male falls at work and sustains a fracture of his left fibula. In the emergency room, a complete blood cell count reveals:

Hemoglobin: 12.9 g/dL
Hematocrit: 38%
White blood cell count: 8.9 x 103 cells/mm3
Mean corpuscular volume: 66 fL
Platelet count: 300,000/mm3

He has no past medical history. He is released from the hospital with a cast. Follow-up laboratory testing performed four weeks later reveals:

Serum iron: 120 µg/dL
Total iron binding capacity: 402 µg/dL
Ferritin: 160 ng/mL

A hemoglobin electrophoresis reveals no abnormalities. Of the following, what is the most likely diagnosis?

A. α-thalassemia
B. β-thalassemia
C. Sickle cell anemia
D. Iron deficiency anemia
E. Anemia of chronic disease

Answer for Question 147

Answer: A (α-thalassemia)

Explanation: The patient has a markedly low MCV and only a mildly decreased hemoglobin. The serum iron, TIBC and ferritin concentrations are normal. Given he is a young otherwise healthy male, iron deficiency is very unlikely, and not supported by the laboratory testing. An asymptomatic thalassemia is possible. Given his Asian ancestry, an α-thalassemia would be most likely. In a hemoglobin electrophoresis, patients with α-thalassemia will be normal; patients with β-thalassemia would have an elevated amount of hemoglobin A2 and hemoglobin F. In sickle cell anemia, the hemoglobin electrophoresis would not be normal, and the patient does not have a chronic disease process (eliminating anemia of chronic disease).

Question 148

A 20-year-old Greek male college student slips and falls in the cafeteria, hitting his head. He is subsequently taken to the emergency room, where a complete blood cell count reveals:

Hemoglobin: 12.7 g/dL
Hematocrit: 37%
White blood cell count: 10.2 x 103 cells/mm3
Mean corpuscular volume: 67 fL
Platelet count: 290,000/mm3

He has no past medical history. He is released from the emergency room after a period of observation and a negative CT scan of the head. Follow-up laboratory testing performed four weeks later reveals:

Serum iron: 132 µg/dL
Total iron binding capacity: 356 µg/dL
Ferritin: 157 ng/mL

A hemoglobin electrophoresis reveals no abnormalities. Of the following, which is the most likely underlying genetic defect responsible for his red blood cell abnormality?

A. Gene deletion
B. Mutation in gene for hemoglobin resulting in no production
C. Mutation in gene for hemoglobin resulting in decreased production
D. Isochromosome
E. Translocation

Answer for Question 148

Answer: A (Gene deletion)

Explanation: The patient has a markedly low MCV and only a mildly decreased hemoglobin. The serum iron, TIBC, and ferritin concentrations are normal. Given he is a young otherwise healthy male, an asymptomatic thalassemia is possible. Given his Mediterranean ancestry, an α-thalassemia is possible. In a hemoglobin electrophoresis, patients with α-thalassemia will be normal; patients with β-thalassemia would have an elevated amount of hemoglobin A2 and hemoglobin F. The underlying cause of α-thalassemia is a gene deletion. β-thalassemia is due to a mutation in the hemoglobin gene that causes either no production or decreased production. Isochromosomes and chromosomal translocations are not normally associated with thalassemia.

Questions 143-145: Hematopathology

Question 143

A 63-year-old male with a past medical history of well-controlled hypertension reports to his family physician that over the past 6 months he has had increasing fatigue, weakness, a lack of appetite with a resultant 10 lb. weight loss, and a generalized malaise. A complete blood cell count reveals:

Hemoglobin: 12.2 g/dL
Hematocrit: 36%
White blood cell count: 45 x 103 cells/mm3
Platelet count: 600,000/mm3

The doctor suspects a chronic leukemia, but would like to rule out a leukemoid reaction caused by a smoldering infection. Which of the following laboratory tests would best assist in this distinction?

A. Serum protein electrophoresis
B. Lactate dehydrogenase
C. Leukocyte alkaline phosphatase
D. Repeat the white blood cell count
E. Alanine aminotransferase

Answer for Question 143

Answer: C (Leukocyte alkaline phosphatase)

Explanation: In a leukemoid reaction, the white blood cell count can be markedly elevated, and 45,000 cells/mm3 would be easily possible. In a leukemoid reaction, the white blood cells are functioning normally and an increased amount of leukocyte alkaline phosphatase would be expected; however, in CML the leukocyte alkaline phosphatase is commonly low.

Question 144

A 61-year-old male with a past medical history of well-controlled hypertension and hyperlipidemia reports to his family physician that over the past 12 months he has had increasing fatigue, weakness, and a lack of appetite with a resultant 20 lb. weight loss. A complete blood cell count reveals:

Hemoglobin: 11.8 g/dL
Hematocrit: 38%
White blood cell count: 52 x 103 cells/mm3
Platelet count: 560,000/mm3

Physical examination reveals mild splenomegaly. A peripheral smear would reveal which of the following?

A. An increased number of mature and maturing granulocytes
B. Blasts with a minimal amount of cytoplasm
C. Blasts with a prominent amount of cytoplasm
D. Numerous plasma cells
E. Schistocytes
F. Bite cells
G. Red blood cells with parasites

Answer for Question 144

Answer: A (An increased number of mature and maturing granulocytes)

Explanation: The clinical scenario (an older male) presenting over time with a disease process, with an elevated white blood cell count, elevated platelet count, and mild anemia, and with splenomegaly on the physical examination is consistent with a chronic leukemia. An increased number of mature and maturing granulocytes is consistent with chronic myeloid leukemia. Blasts would be consistent with an acute leukemia, which would present over the course of days to weeks. Numerous plasma cells could indicate multiple myeloma; however, these patients often present with bone pain or signs/symptoms related to hypercalcemia or renal disease.

Question 145

A pathologist is reviewing a blood smear. Numerous red blood cells on the slide have a single peripheral extension from the edge of the cell. Of the following, what is the most likely diagnosis for the patient?

A. Cirrhosis of the liver
B. End-stage kidney disease
C. Myelofibrosis
D. Disseminated intravascular coagulation
E. Hereditary spherocytosis

Answer for Question 145

Answer: C (Myelofibrosis)

Explanation: Red blood cells with a single peripheral extension from the edge of the cell are tear drop cells (i.e., dacrocyte). Tear drop cells are most commonly associated with bone marrow fibrosis. Both burr cells and spur cells (i.e., acanthocytes) have extensions from the periphery of the cell, but the extensions are numerous. Burr cells have regularly distributed extensions and are seen most commonly as artifact; however, they also occur in liver disease and uremia. Spur cells have numerous extensions but they are irregularly distributed. Spur cells are seen in liver disease, abetalipoproteinemia, and McLeod syndrome. Schistocytes have extensions of at least two ends (or, at least two ends of the cell are pointed) and are fragmented. They are associated with DIC. In hereditary spherocytosis, the red blood cells are smaller and contracted with no central pallor.

Questions 140-142: Hematopathology

Question 140

A 54-year-old female with a long-standing history of Sjogren syndrome develops a slowly growing mass in her left submandibular gland. Genetic analysis of the mass is most likely to reveal which of the following translocations?

A. t(8;14)
B. t(9;22)
C. t(11;18)
D. t(12;21)
E. t(15;17)

Answer for Question 140

Answer: C (t(11;18))

Explanation: Patients with autoimmune diseases are at risk for extranodal marginal zone lymphoma, and patients with Sjogren syndrome can develop the lymphoma in a salivary gland. t(11;18) as well as t(14;18) are associated with extranodal marginal zone lymphomas. t(8;14) is associated with Burkitt lymphoma; t(9;22) with CML and ALL; t(12;21) with ALL, and t(15;17) with acute promyelocytic leukemia.

Question 141

Over the past two days, a 13-year-old boy has had one week of diarrhea and abdominal cramping, and then has not passed feces for 2 days. His parents are concerned and have brought him to the emergency room for evaluation. A CT scan of the abdomen reveals a mass at the ileocecal junction and a distended small intestine. Resection of the mass reveals a monomorphous population of large cells with interspersed macrophages containing cellular debris. Of the following, which would genetic analysis of the tumor cells reveal?

A. t(8;14)
B. t(9;22)
C. t(11;14)
D. t(14;18)
E. t(15;17)

Answer for Question 141

Answer: A (t(8;14))

Explanation: The clinical scenario is consistent with Burkitt lymphoma, which most often occurs in children and young adults, and is often found at the ileocecal junction and can cause a bowel obstruction. The histologic description is consistent with Burkitt lymphoma, with the interspersed macrophages containing cellular debris representing the characteristic starry sky pattern. t(8;14) as well as t(2;8) and t(8;22) are associated with Burkitt lymphoma. The MYC protooncogene is on chromosome 8 and the Ig heavy chain gene is on 14, resulting in increased production of MYC.

Question 142

A 57-year-old male with a past medical history of type II diabetes reports to his family physician that over the past 6 months he has felt increasingly tired and unable to complete tasks at work or at home without resting. Occasionally, he has had a fever. He has also lost 15 lbs., which he knows is good for his diabetes. A complete blood cell count reveals:

Hemoglobin: 12.2 g/dL
Hematocrit: 36%
White blood cell count: 45 x 103 cells/mm3
Platelet count: 600,000/mm3

A physical examination reveals an enlarged spleen. Genetic analysis reveals a t(9;22). Of the following, what is the most likely diagnosis?

A. Acute lymphoblastic leukemia
B. Chronic lymphoblastic leukemia
C. Acute myelogenous leukemia
D. Chronic myeloid leukemia

Answer for Question 142

Answer: D (Chronic myeloid leukemia)

Explanation: Given the slow development of symptoms (i.e., their insidious nature), an acute leukemia is not very likely, as these present acutely over days to weeks, and usually not months. While the demographics are consistent with both CLL and CML, as is the splenomegaly, the t(9;22) is found in CML. t(9;22) is also found in adult ALL; however, given the slow development of the symptoms, an acute process is not likely; also, acute leukemia tends to present with pancytopenia, whereas this patient has an elevated platelet count as can be found in CML.

Questions 137-139: Hematopathology

Question 137

During a routine appointment, a 60-year-old man’s dentist palpates some lymph nodes on the right side of the neck. A follow-up physical with a family practitioner reveals additional lymph nodes in the right axilla and the left femoral region. The lymph nodes are painless but rubbery to palpation. Biopsy of the lymph nodes is most likely to reveal which of the following?

A. A starry sky pattern
B. Reed-Sternberg cells
C. Granulomas
D. Nodular effacement of the architecture
E. Metastatic glioblastoma multiforme

Answer for Question 137

Answer: D (Nodular effacement of the architecture)

Explanation: The clinical presentation (painless enlargement of lymph nodes in non-contiguous locations) is consistent with non-Hodgkin lymphoma. Nodular effacement of the architecture describes follicular lymphoma, which is a common non-Hodgkin lymphoma in older patients. A starry sky pattern is characteristic of Burkitt lymphoma, which normally presents in a younger population. Reed-Sternberg cells are characteristic of Hodgkin lymphoma, which involves contiguous groups of lymph nodes. CNS tumors very rarely metastasize. The history does not support a granulomatous process, such as tuberculosis or a non-typical infection, and sarcoid just involving a group of lymph nodes without additional organ involvement would be unlikely.

Question 138

During a yearly physical examination, the primary care physician for a 60-year-old man palpates lymph nodes on both sides of the neck and in the right femoral region. A subsequent biopsy of the lymph nodes is most likely to reveal a nodular effacement of the architecture. Genetic testing would reveal which of the following?

A. t(8;14)
B. t(8;21)
C. t(9;22)
D. t(14;18)
E. t(12;21)
F. t(15;17)

Answer for Question 138

Answer: D (t(14;18))

Explanation: The involvement of non-contiguous lymph nodes is consistent with a non-Hodgkin lymphoma. Nodular effacement of the architecture is a description that is consistent with a follicular lymphoma, which involves older adults. Follicular lymphoma is associated with a t(14;18), which moves the bcl-2 gene adjacent to the Ig heavy chain gene. t(8;14) is associated with Burkitt lymphoma; t(8;21) and t(15;17) with acute myeloid leukemia; t(9;22) with CML and ALL; and t(12;21) with ALL.

Question 139

A 61-year-old male for the past year has had multiple infections, including two episodes of pneumonia and two abscesses in the skin requiring drainage. Prior to that, he had been very healthy, only requiring treatment for hypertension that developed 5 years ago. A physical examination reveals palpable lymph nodes in the left femoral region and right axilla. Of the following, which test is likely to disclose the cause for his repeated infections?

A. Serum ferritin
B. Serum protein electrophoresis
C. CT scan of the chest to assess the thymus
D. EKG
E. Thyroid function testing

Answer for Question 139

Answer: B (Serum protein electrophoresis)

Explanation: The finding of enlarged lymph nodes in non-contiguous locations is consistent with a non-Hodgkin lymphoma. Non-Hodgkin lymphoma of certain types (e.g., SLL) can be associated with a hypogammaglobulinemia. Patients with a hypogammaglobulinemia can be at risk for serious bacterial infections. A serum protein electrophoresis or a urine protein electrophoresis can identify a hypogammaglobulinemia.

Questions 134-136: Hematopathology

Question 134

A 35-year-old male presents to his primary care physician. Over the past 4 months he has felt a lump in his neck. Palpation reveals a painlessly enlarged lymph node. He has no past medical history and and review of systems is negative. Biopsy of the lymph node reveals occasional large binucleated cells with prominent nucleoli in a background of mixed inflammatory cells including eosinophils. The large cells are CD15 positive. Of the following markers, which is most likely to also be positive in these large cells?

A. CD5
B. CD20
C. CD30
D. CD45
E. CD103

Answer for Question 134

Answer: C (CD30)

Explanation: The histologic description is that of mixed cellularity Hodgkin disease, with the large cells being Reed-Sternberg cells. The clinical presentation of painless cervical lymphadenopathy is also consistent with Hodgkin disease. Reed-Sternberg cells are positive for CD15 and CD30, but negative for CD45 (common leukocyte antigen) as well as CD20 (B cell marker), CD5 (T cell marker) and CD103, which is found in hairy cell leukemia.

Question 135

A 56-year-old male presents to his primary care physician. Over the past 6 months, he has had frequent sweating at night, sometimes which drenches his bed clothes. Review of systems reveals occasional subjective fevers and a 15 lb. weight loss over the past several months. His past medical history includes diet-controlled diabetes mellitus and hypertension. A chest x-ray reveals enlarged mediastinal lymph nodes. A biopsy of one of the involved lymph nodes reveals scattered large binucleated cells in a background of mixed inflammatory cells. Infection with which of the following viruses is associated with the change in the lymph node?

A. CMV
B. EBV
C. HTLV
D. Hepatitis C
E. HIV
F. HSV

Answer for Question 135

Answer: B (EBV)

Explanation: The binucleated cells in a background of mixed inflammatory cells, presenting as mediastinal lymphadenopathy in a patient with B symptoms (weight loss, fever, and night sweats), is consistent with mixed cellularity Hodgkin lymphoma, which is bimodal in distribution and affects patients around 50-60 years of age. Of the viruses listed, Hodgkin lymphoma is associated with EBV.

Question 136

Over the past two days, a 12-year-old boy has had episodes of diarrhea and abdominal cramping. At first, his parents attributed it to a virus that was going around town, but then decided to take him to the emergency room when his symptoms did not improve. At CT scan of his abdomen reveals a mass at the ileocecal junction. If the mass is determined to be malignant, which of the following is the most likely diagnosis?

A. Follicular lymphoma
B. Mantle cell lymphoma
C. Extranodal marginal zone lymphoma
D. Burkitt lymphoma
E. Mycoses fungoides

Answer for Question 136

Answer: D (Burkitt lymphoma)

Explanation: In the United States, Burkitt lymphoma commonly involves the gastrointestinal tract, often at the ileocecal junction. Follicular lymphoma, mantle cell lymphoma, and extranodal marginal zone lymphoma are more frequently identified in adults and adolescents. Mycoses fungoides affects the skin.