[C] 1.30 Hyalinosis, fibrinoid necrosis

Question 1

Hyalinosis

Answer 1

Hyalinoid degeneration

• Products are stained pink with eosin and are spread around the body
• Can be physioligical / Pathological

Question 2

Physiological hyalinosis

Answer 2

In the blood vessels of the uterus, during involution

Question 3

Pathological hyalinosis

Answer 3

• Connective tissue origin
• Cellular origin
• Hematogenous origin

Question 4

Extracellular hyalinosis of connective tissues

Answer 4

• Connective tissue matrix is swollen & homogenously stained
• Appearance: Local and/or systemic
• Causes:
  
  • Often immunopathological
  • Tissue acidosis (↑ water binding capacity of the fibres)
    
    • Typically seen in scars

Question 5

Extracellular hyalinosis due to immunopathologic processes

Answer 5

Ag + ab = Systemic form (in Ig-producing organs)

Ag + Ab = Local form (at the site of tissue degradation)

Question 6

Staining reactions of EC hyalin

Answer 6

• Responds positively to Millon’s & Xantoproteic tests
• Strongly acidophilic with acid stains (Eosin, acid fuchsine)
• Resistant to acids and alkalis: Not soluble

Question 7

Intracellular hyalinosis

Answer 7

• In epithelial cells
• Following cell destruction
• Hyperactive plasma cells

Question 8

IC hyalinosis:

• Epithelial cells

Answer 8

Deposition-type hyalinosis

• In the tubular epithelial cells of the kidney hyalin droplet degeneration

Question 9

IC hyalinosis:

• Following cell destruction

Answer 9

• Mallory body
• Autophage vacuoles
• Councilman body in the liver

Question 10

IC hyalinosis:

• In hyperactive plasma cells

Answer 10

Russel-bodies (Fuchsinophil bodies)

Question 11

Give the types of IC hyalinosis

Answer 11

1. Intact cell
2. Autophage vacuole
3. Mallory-body
4. Councilman-body

Question 12

Hematogenous hyalinosis can occur in

Answer 12

• In the wall of blood vessels - E.g Swine fever
• Hyalin membrane - E.g pulmonary membrane
• Hyalinised fibrin - E.g in thrombi
• Hyaline cylinder - E.g in the lumen of the tubuli
• Corpus amylaceum E.g In the acini of glands
• Caoutchouc hyalin E.g in follicles of the thyroid

Question 13

Macroscopic changes in hyalinosis can occur in which forms?

Answer 13

• Extracellular hyalinosis
• Intracellular hyalinosis
• Haemotogenous hyalinosis

Question 14

Macroscopic EC hyalinosis

Answer 14

• Visible only in severe cases
• Smaller or larger swelling of the affected area
• Diagnosis must be confirmed by histopathology

Question 15

Macroscopic IC hyalinosis

Answer 15

Recognised in histological section

Question 16

Macroscopic haematognous hyalinosis

Answer 16

• Sometimes visible during dissection
• Usually seen with histopathology

Question 17

Fibrinoid necrosis: Etiology

Answer 17

• In the wall of the blood vessels
• In the connective tissues

Question 18

Fibrinoid necrosis: In general

Answer 18

Deposition of homogenous substance & necrosis → Basic characteristics change

Question 19

Fibrinoid necrosis in small, medium & large blood vessels

Answer 19

1. Serum (containing fibrinogen) accumulates in the media
2. The affected area necrotises
3. Lesions appear in nodular form in the blood vessels - Changes can be circumscribed, irregular and uneven

Question 20

Fibrinoid necrosis in connective tissue

Answer 20

1. Collagen fibres swell and necrotise
2. Around the necrotised tissue, reactive inflammation occurs

Question 21

Causes of fibrinoid necrosis

Answer 21

Immune processes:

1. Antigen + Antibody = Immunocomplexes
2. Inflammatory reactions triggered by the immunocomplexes

E.g :

• Poliarteriitis nodosa
• Rheumatoid arthritis

Antigen is known only in some cases