Eye

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The eye is rarely seen by pathologists. Typically, they go to neuropathologists, as the eye is really part of the brain. The article also covers lesions found around the eye. The lacrimal gland is covered in the lacrimal gland article.

An introduction to neuropathology is in the neuropathology article.

Procedures

  • Evisceration - eye muscles left intact.
  • Enucleation.
  • Exenteration - extensive resection.

Anatomy

Anterior to posterior

  1. Cornea.
  2. Iris.
  3. Lens.
  4. Conjunctiva - edge of cornea.
  5. Sclera.
    • Similar to cornea - normally has blood vessels.

Optic nerve

  • Surrounded by CSF.
  • Covered by dura.

Inside to outside

  1. Retina.
  2. Retinal pigment epithelium (RPE).
  3. Choroid.
  4. Sclera.

Anterior angle

  • Angle between cornea and iris.

Histology

Eye muscles

  • The muscles that move the eye have a high nerve:muscle ratio = ~1:4.[1]
    • Other muscles in the body ~1:250.

Conjunctiva

Features:[2]

  • Stratified squamous.
    • May be stratified columnar
  • Goblet cells.

Cornea

Layers:[3]

  1. Epithelium layer.
    • Squamoid cells.
  2. Bowman's layer.
    • Indistinct.
  3. Stroma.
    • Fibrous tissue.
    • No blood vessels.
  4. Descemet’s layer.
    • Indistinct.
    • PAS -ve.
  5. Endothelium.
    • Single layer.

Eye structures with melanocytes

Melanoma may arise from these sites:

  • Iris.
  • Conjunctiva.
  • Ciliary bodies.
  • Choroid.

Benign entities

Conjunctivitis

General

  • Benign.
  • Never biopsied.
    • It is an incidental finding in a biopsy for something else.

Gross

  • Red eye.

Microscopic

Features:

  • Conjunctival epithelium - stratified squamous epithelium with goblet cells.
  • Inflammatory cells.

Pinguecula

  • Plural Pingueculae.

General

  • Raizada et al.[4] suggest it is an early pterygium; however, this is disputed.
  • Due to ultraviolet light exposure, e.g. sunlight.[5]
  • Tend to be older than individuals afflicted with a pterygium.

Gross

  • Yellow spot.

Microscopic

Features:

  • Similar to pterygium.[5]

Pterygium

  • AKA surfer eye.

General

  • Pronounced: "tuh-rij-ee-uhm".[6]
  • Conjunctiva lesion that covers part of the sclera.
    • Sclera = white part of the eye.[7]
  • Benign.
  • Due to ultraviolet light exposure, i.e. sunlight.[5]

Gross

  • Medial aspect of eye - covers sclera (white part) and part of the iris (coloured part).

Image:

Microscopic

Features:[5]

  • Hyaline material beneath epithelium.
  • Elastic fibres beneath the hyaline material.
  • +/-Inflammation.
  • Solar elastosis.[8]
    • Dense gray/light brown acellular material.
  • Dilated vessels.[8]

DDx:

Images:

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CONJUNCTIVA ("PTERYGIUM"), RIGHT, EXCISION:
- SQUAMOUS EPITHELIUM WITH GOBLET CELLS, SOLAR ELASTOSIS AND DILATED SUPERFICIAL BLOOD VESSELS -- CONSISTENT WITH PTERYGIUM.

Eccrine hidrocystoma

  • Occasionally spelled eccrine hydrocystoma.[10]

General

  • Benign.
  • Eyelid lesion.

Clinical DDx:[10]

Microsopic

Features:

Chalazion

General

  • Benign eye thing.

Microscopic

Features:

Image:

Retinal hemorrhage

See Traumatic brain injury in infants.

Image:

Glaucoma

General

  • Leading cause of irreversible blindness.

Classification:

  • Open angle - more common.
  • Closed angle.

Microscopic

Features (closed angle):

  • Cornea and iris opposed to one another.

Retinal detachment

General

  • Blindness.

Causes:

  • Trauma (classic) - pathologist doesn't usually see.
  • Tumours - common in pathology specimens.

Microscopic

Features:

  • Retina separated from retinal pigment epithelium.
  • Eosinophilic exudate containing macrophages.

Malignant entities

Retinoblastoma

General

  • Rare.
  • Malignant.
  • May be familial.[15]

Gross

  • White, solid.
  • Patterns:
    • Endophytic - grow into the vitreous cavity.
    • Exophytic - grow toward choroid.
    • Mixed - components of endophytic and exophytic.

Image:

Note:

  • Tumour is extremely friable.

Microscopic

Features:

  • Small round cell tumour:
    • Scant cytoplasm.
  • Flexner-Wintersteiner rosette - key feature.
    • Rosette with empty centre (donut hole).[16]
  • +/-Homer-Wright rosette.[17]
    • Circular rosette with neuropil at the centre.[16]
  • Mitoses - common.
  • +/-Necrosis.
  • +/-Calcification.

DDx:

  • Retinocytoma (retinoma) - benign counterpart of retinoblastoma.

Notes:

  • DDx of Flexner-Wintersteiner rosette includes:
    • Pineoblastoma.
    • Medulloepithelioma.

Image:

Malignant melanoma

Main article: Malignant melanoma

Common malignancy in the eye in adults.

See also

References

  1. ↑ Bilbao. 24 November 2010.
  2. ↑ URL: http://www.lab.anhb.uwa.edu.au/mb140/corepages/eye/eye.htm. Accessed on: 20 October 2011.
  3. ↑ URL: http://www.ophthobook.com/questions/question-name-the-layers-of-the-cornea-and-their-function. Accessed on: 26 January 2012.
  4. ↑ Raizada, IN.; Bhatnagar, NK. (Jul 1976). "Pinguecula and pterygium (a histopathological study).". Indian J Ophthalmol 24 (2): 16-8. PMID 1031388.
  5. ↑ 5.0 5.1 5.2 5.3 Hill, JC.; Maske, R. (1989). "Pathogenesis of pterygium.". Eye (Lond) 3 ( Pt 2): 218-26. doi:10.1038/eye.1989.31. PMID 2695353.
  6. ↑ URL: http://dictionary.reference.com/browse/pterygium. Accessed on: 20 October 2011
  7. ↑ URL: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002006/. Accessed on: 20 October 2011.
  8. ↑ 8.0 8.1 URL: http://www.uic.edu/depts/mcpt/eyepath/specco4.htm. Accessed on: 25 October 2011.
  9. ↑ Clear, AS.; Chirambo, MC.; Hutt, MS. (Feb 1979). "Solar keratosis, pterygium, and squamous cell carcinoma of the conjunctiva in Malawi.". Br J Ophthalmol 63 (2): 102-9. PMC 1043407. PMID 427069. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1043407/.
  10. ↑ 10.0 10.1 10.2 Adams, SP. (Feb 1999). "Dermacase. Eccrine hydrocystoma.". Can Fam Physician 45: 297, 306. PMC 2328272. PMID 10065300. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2328272/.
  11. ↑ D'hermies, F.; Fayet, B.; Meyer, A.; Morel, X.; Halhal, M.; Elmaleh, C.; Azan, F.; Behar-Cohen, F. et al. (Feb 2004). "[Chalazion mimicking an eyelid tumor].". J Fr Ophtalmol 27 (2): 202-5. PMID 15029054.
  12. ↑ URL: http://emedicine.medscape.com/article/1212709-workup. Accessed on: 9 February 2012.
  13. ↑ URL: http://www.surgical-pathology.com/chalazion.htm. Accessed on: 24 January 2012.
  14. ↑ URL: http://library.med.utah.edu/WebPath/EXAM/IMGQUIZ/fofrm.html. Accessed on: 6 December 2010.
  15. ↑ Lohmann D (2010). "Retinoblastoma". Adv. Exp. Med. Biol. 685: 220–7. PMID 20687510.
  16. ↑ 16.0 16.1 Wippold FJ, Perry A (March 2006). "Neuropathology for the neuroradiologist: rosettes and pseudorosettes". AJNR Am J Neuroradiol 27 (3): 488–92. PMID 16551982.
  17. ↑ WH. 14 March 2011.
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