BMS Pathology and Microbiology 3 — Questions and Answers
Question 1: Which type of granuloma, characterized by central caseation necrosis, is pathognomonic of tuberculosis?
- Caseating granuloma (Correct answer)
- Foreign body granuloma
- Sarcoidal granuloma
- Suppurative granuloma
Correct answer: Caseating granuloma
Caseating granulomas with central cheesy necrosis surrounded by epithelioid histiocytes and Langhans giant cells are characteristic of Mycobacterium tuberculosis infection.
Question 2: A decedent's liver shows a large abscess containing 'anchovy paste' material. Which organism is most likely responsible?
- Entamoeba histolytica (Correct answer)
- Staphylococcus aureus
- Echinococcus granulosus
- Aspergillus fumigatus
Correct answer: Entamoeba histolytica
E. histolytica produces hepatic abscesses with characteristic reddish-brown 'anchovy paste' or 'chocolate sauce' contents due to liquefied necrotic hepatocytes.
Question 3: Which cell type predominates in a chronic inflammatory infiltrate observed histologically?
- Lymphocytes and macrophages (Correct answer)
- Neutrophils
- Eosinophils
- Basophils
Correct answer: Lymphocytes and macrophages
Chronic inflammation is characterized by lymphocytes, macrophages, and plasma cells rather than the neutrophils seen in acute inflammation.
Question 4: During embalming, the formaldehyde-based solution acts as a fixative primarily by:
- Cross-linking proteins (Correct answer)
- Denaturing lipids
- Precipitating carbohydrates
- Chelating metal ions
Correct answer: Cross-linking proteins
Formaldehyde creates methylene bridge cross-links between amino groups of proteins, halting autolysis and microbial decomposition.
Question 5: Which stain is used to identify acid-fast organisms such as Mycobacterium tuberculosis in tissue sections?
- Ziehl-Neelsen stain (Correct answer)
- Hematoxylin and eosin
- Alcian blue
- Masson trichrome
Correct answer: Ziehl-Neelsen stain
The Ziehl-Neelsen (carbol-fuchsin) stain highlights mycobacteria as bright red rods on a blue background due to their waxy cell walls.
Question 6: A 45-year-old decedent has bilateral pleural effusions and ascites at autopsy. This pattern of fluid accumulation is best described as:
- Anasarca (Correct answer)
- Hemothorax
- Pyothorax
- Chylothorax
Correct answer: Anasarca
Anasarca is generalized edema involving body cavities and subcutaneous tissue, commonly resulting from heart failure, cirrhosis, or nephrotic syndrome.
Question 7: Which hepatitis virus is transmitted exclusively via the parenteral route and has no vaccine available?
- Hepatitis C (Correct answer)
- Hepatitis A
- Hepatitis B
- Hepatitis E
Correct answer: Hepatitis C
Hepatitis C is transmitted through blood/needles; unlike HBV, no approved vaccine exists, and it frequently leads to chronic liver disease.
BMS Pathology and Microbiology 3
Which type of granuloma, characterized by central caseation necrosis, is pathognomonic of tuberculosis?