Pathology
Histopathology
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Haematoxylin and eosin
Features
Haematoxylin (basic) stains acidic structures purplish/blue eg DNA, ribosomes, rEREosin (acidic) stains basic structures red or pink eg most cytoplasmic proteins and amyloid
Uses
Commonly used
Periodic acid-Schiff
Features
Outlines tissue structures eg. BMs, capsules, blood vessels
Uses
Acanthomoeba cysts and fungi
PAS-positive material in homocystinuria
Alcian blue
Features
Highlights mucopolysaccharide
Uses
Corneal macular dystrophy
Colloidal iron
Features
Stains mucopolysaccharide blue
Uses
Corneal macular dystrophy
Congo red
Features
Highlights amyloid with 'apple' green birefringence
Uses
Corneal lattice dystrophy
Masson trichrome
Features
Highlights hyaline materials red
Highlights new collagen blue
Uses
Corneal granular dystrophy
Reis-Buckler epithelial dystrophy
Perl's prussian blue
Features
Intracellular corneal epithelial iron causing Fleischer rings
Stocker line of iron at the advancing edge of a pterygium
Ferry line at base of trabeculectomy bleb
Uses
Fleischer rings: Keratoconus
Stocker line: pterygium
Ferry line: trab bleb
Gram stain
Features
Gentian violet and Lugol's iodine create a blue/black complex on the charged bacterial cell wall (gram positive)
Uses
Gram positive vs Gram negative species
Ziehl-Neelsen
Features
Mycobacteria
Uses
Acid-fast bacilli (TB)
Grocott hexamine/methanamine
Features
Black
Uses
Fungi and acanthomoeba
Calcoflour white
Features
Requires fluorescent microscope
Uses
Fungi (and acanthomoeba?)
Acridine orange
Features
Requires fluorescent microscope
Uses
Fungi
Giemsa
Features
Blue-purple inclusion bodies
Uses
Chlamydia
(Fungi)
DNA: reveals alternating bands
Oil red O
Features
Stains fat within cells red
Uses
Sebaceous cell carcinoma
Sudan black
Features
Stains lipid
Uses
Sebaceous cell carcinoma
Von Kossa
Features
Stains calcium black
Uses
| Stain | Features | Uses |
| Haematoxylin and eosin | Haematoxylin (basic) stains acidic structures purplish/blue eg DNA, ribosomes, rEREosin (acidic) stains basic structures red or pink eg most cytoplasmic proteins and amyloid | Commonly used |
| Periodic acid-Schiff | Outlines tissue structures eg. BMs, capsules, blood vessels | Acanthomoeba cysts and fungiPAS-positive material in homocystinuria |
| Alcian blue | Highlights mucopolysaccharide | Corneal macular dystrophy |
| Colloidal iron | Stains mucopolysaccharide blue | Corneal macular dystrophy |
| Congo red | Highlights amyloid with ‘apple’ green birefringence | Corneal lattice dystrophy |
| Masson trichrome | Highlights hyaline materials redHighlights new collagen blue | Corneal granular dystrophyReis-Buckler epithelial dystrophy |
| Perl’s prussian blue | Intracellular corneal epithelial iron causing Fleischer ringsStocker line of iron at the advancing edge of a pterygiumFerry line at base of trabeculectomy bleb | Fleischer rings: Keratoconus Stocker line: pterygiumFerry line: trab bleb |
| Gram stain | Gentian violet and Lugol’s iodine create a blue/black complex on the charged bacterial cell wall (gram positive) | Gram positive vs Gram negative species |
| Ziehl-Neelsen | Mycobacteria | Acid-fast bacilli (TB) |
| Grocott hexamine/methanamine | Black | Fungi and acanthomoeba |
| Calcoflour white | Requires fluorescent microscope | Fungi (and acanthomoeba?) |
| Acridine orange | Requires fluorescent microscope | Fungi |
| Giemsa | Blue-purple inclusion bodies | Chlamydia (Fungi) DNA: reveals alternating bands |
| Oil red O | Stains fat within cells red | Sebaceous cell carcinoma |
| Sudan black | Stains lipid | Sebaceous cell carcinoma |
| Von Kossa | Stains calcium black |
Giant cells
- Three main types
- Langhan’s cell: horseshoe ring of nuclei
- GCA, sarcoidosis, sometimes TB
- Foreign body giant cell: central nuclei that overlap
Touton’s cell: proliferation of non-Langhans histiocytes. Ring of nuclei enclosing central eosinophilic cytoplasm from peripheral clear cytoplasm.
- Formed by fusion of epithelioid cells
- Seen rarely in xanthogranuloma
Clinical Correlate
Juvenile xanthogranuloma: recurrent hyphaemas and yellow-orange skin papules
Hot Topic
Histological findings in certain diseases
| Disease entity | Histological findings |
Neurilemmoma -benign encapsulated tumours of the nerve sheath derived from Schwann cells | Verocay bodies |
| Sarcoidosis | Asteroid and Schaumann bodies |
| Optic nerve sheath meningioma | Psammoma bodiesMeningothelial cells |
| CMV | Owl’s eye inclusion bodies both in the cytoplasm and nucleus |
| HSV, VZV, CMV | Cowdry type A inclusion bodies |
| Cotton wool spots | Cytoid bodies |
Immunohistochemistry
- Imaging of antigens in a tissue section
- Typically uses an antibody
- Visualisation of the antibody-antigen interaction can be achieved in a number of ways
- Enzyme-linked antibodies can induce a colour change
- Antibodies can be linked to fluorophores (eg. fluorescein): immunofluorescence.