ABPath - American Board of Pathology Cardiovascular System Pathology Questions and Answers 1 — Questions and Answers
Question 1: A 17-year-old athlete suddenly collapses and dies during a basketball game. Autopsy reveals a heart weight of 550 grams (normal <350g) with marked, asymmetric thickening of the interventricular septum. Microscopic examination of the septum shows extensive, haphazardly arranged cardiomyocytes with interstitial fibrosis. Which of the following is the most likely diagnosis?
- Arrhythmogenic right ventricular cardiomyopathy
- Dilated cardiomyopathy
- Hypertrophic cardiomyopathy (Correct answer)
- Restrictive cardiomyopathy due to amyloidosis
Correct answer: Hypertrophic cardiomyopathy
The clinical scenario of a young athlete with sudden cardiac death, combined with the gross finding of asymmetric septal hypertrophy and the key microscopic feature of myofiber disarray, is classic for hypertrophic cardiomyopathy (HCM). HCM is the most common cause of sudden cardiac death in young athletes. The histopathologic hallmarks are myocyte hypertrophy, myofiber disarray, and interstitial fibrosis.
Question 2: A 65-year-old male with a history of untreated hypertension presents with a sudden, severe, tearing chest pain radiating to his back. He rapidly develops hypotension and dies. Autopsy reveals a hemopericardium. Which of the following underlying histopathologic findings in the aorta is most strongly associated with this catastrophic event?
- Cystic medial degeneration (Correct answer)
- Atheromatous plaque with intraplaque hemorrhage
- Libman-Sacks endocarditis
- Syphilitic aortitis with vasa vasorum obliteration
Correct answer: Cystic medial degeneration
The clinical presentation is classic for an acute aortic dissection with rupture into the pericardial sac. The most common predisposing histologic lesion for aortic dissection is cystic medial degeneration, which is characterized by the loss of smooth muscle cells and elastic fibers in the aortic media. Hypertension is the single most important risk factor that exacerbates this underlying medial weakness.
Question 3: A 70-year-old man dies suddenly at home five days after being diagnosed with a large transmural anterior wall myocardial infarction. Autopsy is performed. Which of the following is the most likely cause of death?
- Ventricular aneurysm formation
- Rupture of the ventricular free wall (Correct answer)
- Dressler syndrome
- Ventricular arrhythmia
Correct answer: Rupture of the ventricular free wall
Rupture of the ventricular free wall is a catastrophic mechanical complication of MI that typically occurs 3 to 7 days after the event. This timing corresponds to the period of maximal inflammation, with a dense infiltrate of macrophages and neutrophils that release lytic enzymes, leading to significant weakening of the necrotic myocardial wall before sufficient granulation tissue and scarring can provide structural integrity. Ventricular arrhythmias are most common in the first 24-48 hours. Dressler syndrome is a delayed autoimmune pericarditis, usually occurring weeks to months post-MI. A true ventricular aneurysm is a late complication that develops weeks to months after an MI.
Question 4: A biopsy of a mitral valve from a patient with a history of recurrent pharyngitis in childhood and subsequent development of mitral stenosis shows a focal collection of plump macrophages, some of which are multinucleated, admixed with lymphocytes and plasma cells surrounding a central area of fibrinoid necrosis. Some of the macrophages have abundant cytoplasm and central nuclei with wavy, ribbon-like chromatin. What is the pathognomonic term for this inflammatory lesion?
- Granuloma with caseous necrosis
- Infective endocarditis vegetation
- Libman-Sacks endocarditis
- Aschoff body (Correct answer)
Correct answer: Aschoff body
The lesion described is an Aschoff body, which is the pathognomonic finding of acute rheumatic carditis. The characteristic plump macrophages with wavy, 'caterpillar-like' nuclei are known as Anitschkow cells. These lesions are found in the hearts of individuals with rheumatic fever, which is a complication of a group A streptococcal infection.
Question 5: Which of the following cell types is the primary constituent of the fatty streak, the earliest grossly visible lesion of atherosclerosis?
- Lipid-laden macrophages (foam cells) (Correct answer)
- Proliferating smooth muscle cells
- Adherent platelets
- Neutrophils
Correct answer: Lipid-laden macrophages (foam cells)
The fatty streak is the initial lesion of atherosclerosis and is composed primarily of lipid-laden macrophages, also known as foam cells. These cells form when circulating monocytes adhere to the endothelium, migrate into the intima, differentiate into macrophages, and then engulf modified lipoproteins (like oxidized LDL). While smooth muscle cells and lymphocytes are also involved in the progression of the plaque, foam cells define the fatty streak.
Question 6: An explanted heart from a 50-year-old patient with progressive dyspnea and signs of right-sided heart failure shows normal-sized, non-dilated ventricles with marked atrial enlargement. The myocardium is firm and rubbery on sectioning. Endomyocardial biopsy with Congo red staining reveals salmon-pink deposits within the interstitium that exhibit apple-green birefringence under polarized light. These findings are most consistent with which type of cardiomyopathy?
- Dilated cardiomyopathy
- Hypertrophic cardiomyopathy
- Restrictive cardiomyopathy (Correct answer)
- Arrhythmogenic right ventricular cardiomyopathy
Correct answer: Restrictive cardiomyopathy
The clinical and gross findings of non-dilated, stiff ventricles with biatrial enlargement are characteristic of restrictive cardiomyopathy (RCM). The histologic finding of amyloid deposits, confirmed by Congo red staining with apple-green birefringence, identifies cardiac amyloidosis as the specific cause of the RCM. Amyloid deposition in the myocardial interstitium increases ventricular stiffness, impairs diastolic filling, and leads to heart failure.
ABPath - American Board of Pathology Cardiovascular System Pathology Questions and Answers 1
A 17-year-old athlete suddenly collapses and dies during a basketball game.
Autopsy reveals a heart weight of 550 grams (normal <350g) with marked, asymmetric thickening of the interventricular septum.
Microscopic examination of the septum shows extensive, haphazardly arranged cardiomyocytes with interstitial fibrosis.
Which of the following is the most likely diagnosis?