BCSE Pathology 5 — Questions and Answers
Question 1: A 35-year-old woman with long-standing Crohn disease develops right lower quadrant pain. Surgical resection shows transmural inflammation, skip lesions, and creeping fat. Which complication is most characteristic of Crohn disease?
- Toxic megacolon
- Fistula formation (Correct answer)
- Pseudopolyps
- Primary sclerosing cholangitis
Correct answer: Fistula formation
Transmural inflammation in Crohn disease predisposes to fistula formation between loops of bowel, bladder, or skin.
Question 2: A 28-year-old man develops rapidly progressive glomerulonephritis. Renal biopsy shows linear IgG deposits along the glomerular basement membrane. Serum anti-GBM antibodies are positive. What is the diagnosis?
- IgA nephropathy
- Goodpasture syndrome (Correct answer)
- Membranous nephropathy
- Post-streptococcal glomerulonephritis
Correct answer: Goodpasture syndrome
Goodpasture syndrome is caused by anti-GBM antibodies (Type II hypersensitivity) producing linear immunofluorescence and rapidly progressive glomerulonephritis often with pulmonary hemorrhage.
Question 3: Which tumor suppressor gene, when mutated, causes familial adenomatous polyposis (FAP) and dramatically increases colorectal cancer risk?
- BRCA1
- APC (Correct answer)
- RB1
- TP53
Correct answer: APC
APC (adenomatous polyposis coli) gene mutations cause FAP; APC normally targets β-catenin for degradation, and its loss leads to uncontrolled Wnt signaling and polyp formation.
Question 4: A 55-year-old man with hepatitis C cirrhosis develops ascites and jaundice. AFP is markedly elevated. Imaging reveals a 4-cm arterially enhancing liver mass. What is the most likely diagnosis?
- Cholangiocarcinoma
- Hepatocellular carcinoma (Correct answer)
- Metastatic colon cancer
- Hepatic hemangioma
Correct answer: Hepatocellular carcinoma
Hepatocellular carcinoma in the setting of cirrhosis characteristically shows arterial enhancement on imaging and markedly elevated alpha-fetoprotein (AFP).
Question 5: A neonate is found to have a coarctation of the aorta. This defect is most strongly associated with which chromosomal disorder?
- Down syndrome (trisomy 21)
- Edwards syndrome (trisomy 18)
- Turner syndrome (45,X) (Correct answer)
- Klinefelter syndrome (47,XXY)
Correct answer: Turner syndrome (45,X)
Turner syndrome (45,X) is classically associated with coarctation of the aorta and bicuspid aortic valve among its cardiovascular manifestations.
Question 6: A 70-year-old man develops sudden onset back pain radiating to the flank. CT shows a 6-cm abdominal aortic aneurysm (AAA). The most common histologic finding in the aneurysm wall is:
- Cystic medial necrosis
- Atherosclerosis with destruction of the media (Correct answer)
- Granulomatous inflammation
- Fibromuscular dysplasia
Correct answer: Atherosclerosis with destruction of the media
Most abdominal aortic aneurysms are atherosclerotic in origin, with destruction of the elastic media and smooth muscle leading to loss of structural integrity.
Question 7: A pathologist examining a skin biopsy notes proliferating keratinocytes with full-thickness dysplasia that has NOT breached the basement membrane. This lesion is best classified as:
- Invasive squamous cell carcinoma
- Basal cell carcinoma
- Squamous cell carcinoma in situ (Bowen disease) (Correct answer)
- Actinic keratosis
Correct answer: Squamous cell carcinoma in situ (Bowen disease)
Full-thickness keratinocyte dysplasia confined above the intact basement membrane defines squamous cell carcinoma in situ (Bowen disease), a precursor to invasive SCC.
BCSE Pathology 5
A 35-year-old woman with long-standing Crohn disease develops right lower quadrant pain.
Surgical resection shows transmural inflammation, skip lesions, and creeping fat.
Which complication is most characteristic of Crohn disease?