Pathology Cheat Sheet
What the Cell Retains
Intracellular accumulations and calcification: fatty liver, hemosiderin vs lipofuscin, PAS staining, dystrophic vs metastatic calcification, psammoma bodies.
MedNext Academy | 3 min read
What the Cell Retains
Intracellular accumulations and calcification: fatty liver, hemosiderin vs lipofuscin, PAS staining, dystrophic vs metastatic calcification, psammoma bodies.
Intracellular accumulations of lipids, proteins, glycogen and pigments, and the two patterns of pathologic calcification.
High-yield lines
- Fatty change in the liver reflects disturbed triglyceride handling and is confirmed on frozen section with Oil Red O or Sudan stains.
- Macrovesicular steatosis pushes the nucleus to the edge and is relatively benign, while microvesicular steatosis keeps the nucleus central and signals severe mitochondrial dysfunction.
- Microvesicular steatosis occurs in acute fatty liver of pregnancy, Reye syndrome, and tetracycline or valproate toxicity.
- Glycogen is PAS positive and diastase labile, whereas alpha-1-antitrypsin globules are PAS positive and diastase resistant.
- Hemosiderin is an iron storage pigment that stains blue with Perls Prussian blue stain.
- Lipofuscin is a golden-brown wear-and-tear pigment of lipid peroxidation seen in ageing hearts and neurons, producing brown atrophy.
- Melanin stains black with Fontana-Masson and is Prussian blue negative, distinguishing it from hemosiderin.
- Mallory-Denk hyaline is aggregated cytokeratin seen in alcoholic hepatitis, and Russell bodies are immunoglobulin accumulations in plasma cells.
- Dystrophic calcification occurs in dead or damaged tissue with normal serum calcium.
- Metastatic calcification occurs in normal viable tissue due to hypercalcaemia or a raised calcium-phosphate product.
- Psammoma bodies are concentric laminated dystrophic calcifications seen in papillary thyroid carcinoma, serous ovarian carcinoma, meningioma, and mesothelioma.
- Calcium soaps of fat necrosis in acute pancreatitis are a form of dystrophic calcification from saponification.
Mapped competency codes
- PA2.3
- PA2.5
Continue into the full chapter
This summary maps to PA2-cell-injury-and-adaptation.
Frequently Asked Questions
How is dystrophic calcification distinguished from metastatic calcification?
Dystrophic calcification affects damaged tissue with normal serum calcium, while metastatic calcification affects normal tissue in the setting of hypercalcaemia.
How do you distinguish glycogen from alpha-1-antitrypsin on PAS staining?
Both are PAS positive, but glycogen is diastase labile (digested by diastase) whereas alpha-1-antitrypsin globules are diastase resistant.
Which tumours classically show psammoma bodies?
Papillary thyroid carcinoma, serous papillary ovarian carcinoma, meningioma, and mesothelioma.
What does microvesicular steatosis indicate?
Severe mitochondrial dysfunction, as in acute fatty liver of pregnancy, Reye syndrome, and tetracycline or valproate toxicity, carrying a worse prognosis.
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