[C] 1.30 Hyalinosis, fibrinoid necrosis Flashcards
Hyalinosis
Hyalinoid degeneration
- Products are stained pink with eosin and are spread around the body
- Can be physioligical / Pathological
Physiological hyalinosis
In the blood vessels of the uterus, during involution
Pathological hyalinosis
- Connective tissue origin
- Cellular origin
- Hematogenous origin
Extracellular hyalinosis of connective tissues
- 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
Extracellular hyalinosis due to immunopathologic processes
Ag + ab = Systemic form (in Ig-producing organs)
Ag + Ab = Local form (at the site of tissue degradation)
Staining reactions of EC hyalin
- Responds positively to Millon’s & Xantoproteic tests
- Strongly acidophilic with acid stains (Eosin, acid fuchsine)
- Resistant to acids and alkalis: Not soluble
Intracellular hyalinosis
- In epithelial cells
- Following cell destruction
- Hyperactive plasma cells
IC hyalinosis:
- Epithelial cells
Deposition-type hyalinosis
- In the tubular epithelial cells of the kidney hyalin droplet degeneration
IC hyalinosis:
- Following cell destruction
- Mallory body
- Autophage vacuoles
- Councilman body in the liver
IC hyalinosis:
- In hyperactive plasma cells
Russel-bodies (Fuchsinophil bodies)
Give the types of IC hyalinosis
- Intact cell
- Autophage vacuole
- Mallory-body
- Councilman-body
Hematogenous hyalinosis can occur in
- 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
Macroscopic changes in hyalinosis can occur in which forms?
- Extracellular hyalinosis
- Intracellular hyalinosis
- Haemotogenous hyalinosis
Macroscopic EC hyalinosis
- Visible only in severe cases
- Smaller or larger swelling of the affected area
- Diagnosis must be confirmed by histopathology
Macroscopic IC hyalinosis
Recognised in histological section
Macroscopic haematognous hyalinosis
- Sometimes visible during dissection
- Usually seen with histopathology
Fibrinoid necrosis: Etiology
- In the wall of the blood vessels
- In the connective tissues
Fibrinoid necrosis: In general
Deposition of homogenous substance & necrosis → Basic characteristics change
Fibrinoid necrosis in small, medium & large blood vessels
- Serum (containing fibrinogen) accumulates in the media
- The affected area necrotises
- Lesions appear in nodular form in the blood vessels - Changes can be circumscribed, irregular and uneven
Fibrinoid necrosis in connective tissue
- Collagen fibres swell and necrotise
- Around the necrotised tissue, reactive inflammation occurs
Causes of fibrinoid necrosis
Immune processes:
- Antigen + Antibody = Immunocomplexes
- Inflammatory reactions triggered by the immunocomplexes
E.g :
- Poliarteriitis nodosa
- Rheumatoid arthritis
Antigen is known only in some cases
