Question 261
A 53-year-old male dies as the result of blunt force injuries sustained during a motor vehicle accident. The pathologist performing the autopsy identifies a 1.5 cm lesion in the interventricular septum. The microscopic appearance of this lesion is illustrated in the image below. During a conversation with the decedent’s wife, he asks if her husband had complained of chest pain recently, and she says he had. Of the following, how much time elapsed between his chest pain and his death?
A. One or two hours
B. One or two days
C. One or two weeks
D. One or two months
E. One or two years
Answer for Question 261
Answer: C (One or two weeks).
Explanation: This is granulation tissue. In wound repair, granulation tissue usually appears around 4-5 days to one week, and scarring begins at about 2-3 weeks. The granulation tissue is composed of new blood vessels (yellow arrow) and fibrosis (black arrow). There are also scattered lymphocytes (white arrows).
Question 262
A 56-year-old male driver loses control of his vehicle on the ice during a snowstorm and is hit by a semi-truck. He sustains lethal head injuries. A forensic pathologist performs an autopsy and identifies the pathologic condition illustrated in the slide. Of the following, if this individual had survived the car accident, which condition would he have been most at risk for developing?
A. A dilated cardiomyopathy
B. Hemopericardium due to free wall rupture
C. Aneurysm of interventricular septum
D. Acute mitral insufficiency
E. Angiosarcoma of the heart
F. Liposarcoma of the heart
Answer for Question 262
Answer: C (Aneurysm of interventricular septum)
Explanation: The man has a remote infarct of the left ventricle (black, yellow, and white arrow), which involves, in this section, the entire interventricular septum–compare the wall thickness of the interventricular septum to the free wall thickness. Blood pumped against this portion of the wall, which will be essentially unmoving (i.e., not contracting normally), could cause the interventricular septum to bulge into the right ventricle. A remote myocardial infarct is not a risk factor for a dilated cardiomyopathy or angiosarcoma or liposarcoma of the heart. Although there is some discoloration of the postero-medial papillary muscle, this is fibrosis and therefore acute mitral insufficiency would not result. There is no acute full thickness infarct of the left ventricle, so free wall rupture would not be a risk.
Question 263
A 31-year-old female with no significant past medical history presents to an acute care clinic with complaints of chest pain that occurs even when she is resting. Her physical examination discloses a friction rub. Neither physical examination nor chest x-ray reveals any consolidation of the lungs. If the image below is illustrative of the pathologic condition causing her symptoms, of the following, what is the most likely etiology?
A. Massive acute myocardial infarct (2 days old)
B. Metastatic neoplasm
C. Staphylococcal bacterial infection
D. Viral infection
E. Trauma
Answer for Question 263
Answer: D (Viral infection)
Explanation: The heart has a fibrinous pericarditis (bread-and-butter appearance). A common cause is a viral infection. Acute pericarditis (i.e., not Dressler syndrome) occurring after an acute myocardial infarct would only be present on the epicardial surface overlying the infarct area and not the entire heart. A metastatic neoplasm would be unlikely in an otherwise healthy patient, and the exudate is often hemorrhagic. While a Staphylococcal infection of the lung can be associated with an adjacent pericarditis, there is no evidence of a pneumonia by physical examination or imaging. Trauma would be a rare, if ever, cause of fibrinous pericarditis.
Question 264
A 61-year-old male with a past medical history of treated hypertension and a 45 pack-year smoking history dies as the result of a motor vehicle accident. During the autopsy, the forensic pathologist identifies the lesion illustrated below during dissection of the proximal portion of the left anterior descending coronary artery. Examination of the myocardium reveals no pathologic lesion. Of the following, which best explains why no remote infarct was identified?
A. Redundancy of the left anterior descending coronary artery
B. Presence of extensive collateral circulation
C. Protective effects of nicotine
D. Protective effects of hypertension
E. Heterozygosity for LDL receptor mutation
Answer for Question 264
Answer: B (Presence of extensive collateral circulation)
Explanation: The lesion in the coronary artery is a stable plaque (i.e., no acute change), which is producing around 99% stenosis of the lumen. The black arrow indicates that residual lumen of the vessel. Extensive collateral circulation, which could develop as this plaque slowly increased in size, would have protected against a myocardial infarction. Both hypertension and cigarette smoking would have contributed to the development of the plaque, and would not be protective against a myocardial infarct. Heterozygosity for LDL receptor mutation would increase the risk for atherosclerosis; however, it would not explain why an infarct did not occur. While a redundancy of the left anterior descending coronary artery could be protective (i.e., in that flow is now through two vessels instead of one); however, this variation would be very rare, if it even occurred.
Question 265
A 53-year-old male was found dead in his bed by a friend who had come over to take him to a baseball game. On the bed next to him was a syringe with residue that tested presumptively positive for methamphetamine. An autopsy was performed and revealed the histologic change identified below. Of the following, an abnormal concentration of which electrolyte was most likely responsible for causing this change?
A. Magnesium
B. Sodium
C. Potassium
D. Calcium
E. Phosphorus
Answer for Question 265
Answer: D (Calcium)
Explanation: The cardiac myocytes exhibit contraction band necrosis (black arrows). Contraction band necrosis is found in the early stages of an acute myocardial infarct, as a result of reperfusion of a myocardial infarct, and in association with resuscitation or stimulant drug use (e.g., cocaine and methamphetamine). The histologic change is associated with increased concentrations of calcium in the cells.
