NEET-PG Pathology Previous Year Questions (2017–2026)

Correct answer: A. Von Willebrand disease.

The combination of mucocutaneous bleeding (menorrhagia, easy bruising), a prolonged bleeding time, prolonged aPTT with normal PT, impaired ristocetin-induced aggregation and a secondary fall in factor VIII is classic von Willebrand disease. Von Willebrand factor (vWF) does two jobs: it bridges platelets to subendothelium (so its deficiency prolongs the bleeding time and blunts ristocetin aggregation) and it chaperones factor VIII in plasma (so low vWF lowers factor VIII, prolonging the aPTT). The autosomal, both-sexes inheritance fits too.

Incorrect Options:

• B. Haemophilia A: X-linked, affects males, gives deep joint and muscle bleeds with a normal bleeding time and normal ristocetin aggregation.
  
  Haemophilia A: deep haemarthroses, normal bleeding time; ristocetin normal.
• C. Bernard-Soulier syndrome: GPIb defect gives giant platelets and thrombocytopenia; ristocetin fails but factor VIII is normal.
  
  Bernard-Soulier: giant platelets, low count; factor VIII is not reduced.
• D. Glanzmann thrombasthenia: GPIIb/IIIa defect; aggregation fails to all agonists but ristocetin agglutination is preserved and factor VIII is normal.
  
  Glanzmann: absent aggregation to ADP but intact ristocetin; factor VIII normal.

High-Yield Facts:

• Von Willebrand disease is the commonest inherited bleeding disorder, autosomal dominant.
• vWF stabilises factor VIII, so severe deficiency lowers factor VIII secondarily.
• Ristocetin cofactor activity assay is the key functional test.
• Desmopressin (DDAVP) raises vWF and factor VIII in type 1 disease.

Correct answer: C. Perls Prussian blue.

The Perls Prussian blue reaction is the specific stain for haemosiderin. In acid conditions, potassium ferrocyanide reacts with the ferric (Fe3+) iron released from haemosiderin to form an insoluble bright-blue ferric ferrocyanide pigment. This distinguishes true iron-containing haemosiderin from the look-alike golden pigments lipofuscin and bile, which stay negative.

Incorrect Options:

• A. Congo red: Stains amyloid, giving apple-green birefringence under polarised light, not iron.
  
  Congo red highlights amyloid, not haemosiderin.
• B. Masson trichrome: Demonstrates collagen and fibrosis (blue or green), used to grade cirrhosis, not to detect iron.
  
  Masson trichrome shows collagen/fibrosis, not iron pigment.
• D. Periodic acid-Schiff: Stains glycogen, basement membranes and fungal walls magenta, not haemosiderin.
  
  PAS marks glycogen and basement membranes, not iron.

High-Yield Facts:

• Perls Prussian blue is the classic special stain for haemosiderin (ferric iron).
• Chemistry: potassium ferrocyanide plus ferric iron gives insoluble blue pigment.
• Congo red = amyloid; Masson trichrome = collagen; PAS = glycogen.
• Prussian blue positivity in urine (haemosiderinuria) indicates chronic intravascular haemolysis.

Correct answer: B. Heart failure cells.

Chronic left heart failure and mitral stenosis raise pulmonary venous pressure, causing chronic pulmonary congestion and small alveolar micro-haemorrhages. Alveolar macrophages phagocytose the extravasated red cells and store the iron as haemosiderin, becoming heart failure cells. The golden-brown pigment stains blue with Perls Prussian blue, confirming iron. This is the microscopic hallmark of brown induration of the lung.

Incorrect Options:

• A. Anthracotic macrophages: Carry black carbon (soot) pigment from inhaled air pollution, not iron -- Perls is negative.
  
  Anthracosis: black carbon pigment, Perls-negative, unrelated to heart failure.
• C. Lipid-laden macrophages: Contain fat (as in lipoid pneumonia or fat embolism), staining with oil red O, not Perls.
  
  Lipid-laden macrophages hold fat, not iron pigment.
• D. Foamy histiocytes: Lipid-filled macrophages seen in xanthomas and infections -- again not iron-laden congestion cells.
  
  Foamy histiocytes are lipid-rich, distinct from heart failure cells.

High-Yield Facts:

• Heart failure cells are haemosiderin-laden alveolar macrophages of chronic pulmonary congestion.
• They cause brown induration of the lung in chronic left heart failure and mitral stenosis.
• Perls Prussian blue confirms the iron content.
• Anthracosis (carbon) is Perls-negative -- the pigment source is inhaled soot.