Pigmentations

Question 1

Hemosiderin

Answer 1

• derived from catabolism of hemoglobin; partly denatured form of ferritin that easily aggregates
• Histopath:
  
  • H&E: golden-brown
  • Prussian blue: blue
• Body iron stored in erythocytes (75%) and intracell storage pools of ferritin and hemosiderin (25%).
• Hemosiderosis: excess intracell iron accumulation in the form of hemosiderin occuring either by:
  
  • excess intestinal iron absorption
  • hemolysis
  • poorly-regulated transfusions (parenteral)
    *

Question 2

Hemochromatosis

Answer 2

• a form of hemosiderosis of genetically-caused excess iron absorption.
• Pt at risk of cardiac failure, bronze-diabetes,hepatic cirrhosis, and HCC
• Rx: iron metabolism targetting meds

Question 3

Pathologic calcifications 2 main types

Answer 3

1. Dystrophic calcification:

• macroscopic depositin of calcium salts in injured tissues
• initiating factor could be mitochondria of dying cells releasing Ca2+
• Osteopontin protein also play imp. role
• Not associated w abnormalities of Ca2+ metabolism or hypercalcemia.
• requires persistence of necrotic tissue
• common finding in chronic granulomatous infections such as tuberculosis
• Site of dystrophic calcification: coronary arteris and aortic branches.

2. Metastatic calcification

• may occur in normal tissues
• associated w hypercalcemia, chronic renal failure, Vit. D intox, some neoplasms, hyperparathyroidism

Question 4

Gout & Gouty arthritis

Answer 4

• Gout occurs when Pt presents with pain in areas of high MSU concentrations such as joints, big toe (podagra), deposition as spindles under microscopy, +ve birefringent, red
• Note: not all people with hyperurecemia (>7 mg/dl) develop Gout
• Pseudo-gout: Ca2+ deposition showing up as rhomboid shape under microscopy, -ve birefringent, blue, also an example of metastatic calcification
• Cytokine-mediated destruction of:
  
  • articular cartilage lead to gouty arthritis
  • kidney lead to urate nephropathy
• Pathogenesis: HGPRT defect or other enzyme defect (Primary: 90%) or alcohol and/or fatty foods, thiazide drugs, obesity (Secondary: 10%)
• also secondary to chemotherapy where released nucleic acids predisposes to urate crystal formation
• Pathology of gout: early gouty arthritis (acute) will show edematous soft tissues associated w PMN and macroohage w phagocytoised urate crystals; collections of urate crystals are associated w foreign body type of granulomatous inflammation

Question 5

Types of stains

Answer 5

• Oil Red O: adipose tissue
• Prussian blue: hemosiderin
• Congo red: amyloid is birefringent and appear apple-green under polarised light