Bovis ISSN 2398-2993

Ocular squamous cell carcinoma

Contributor(s): Anna Hollis, Vetstream Ltd , Graham Duncanson

Introduction

  • Incidence: most common bovine tumor in any location – according to estimates from inspected abattoirs in the USA, 12.5% of bovine carcass condemnations were due to ocular squamous cell carcinomas.
  • Signs: locally invasive, slow growing, very rare metastases to local lymph nodes, the bony orbit, sinuses, brain or thorax; mainly affects eyelids, lacrimal caruncle, third eyelid, conjunctiva or cornea.
  • Treatment: depends upon the location and extent of tumor, wide surgical excision generally the treatment of choice
  • Prevention: useful in predisposed individuals or geographical areas.
  • Prognosis: overall relatively good depending upon the speed of detection, extent and anatomic position of the lesion(s).

Pathogenesis

Etiology

  • Unknown.
  • Heritability, sunlight, nutrition, eyelid pigmentation and possibly a viral cause are all implicated.
  • Appears to be associated with a high plane of nutrition.
  • In periocular/ocular region postulated causes include:
    • Prolonged or increased exposure to UV light → chronic irritation and inflammation.
    • Light or non-pigmented tissue.
    • Mucocutaneous junctions are predisposed to metaplastic histological changes.
    • Possible viral etiology – infectious bovine rhinotracheitis and papilloma virus have been isolated from the lesions, but the significance is uncertain.

Predisposing factors

General

  • White face.

Specific

  • High UV light intensity, eg at high altitude or tropical/subtropical areas.
  • Aging: chronic exposure.
  • Pink or lightly pigmented eyelids and periocular tissues.

Pathophysiology

  • Locally invasive malignant tumor of mucocutaneous junctions.
  • Slow to metastasize.
  • Three main forms:
    • Proliferative.
    • Ulcerative/destructive.
    • Mixed.
  • Locally invasive, usually slowly growing lesion(s) in areas of non-pigmented skin or mucosa.
  • Advanced cases may occur with invasion of the orbit, ocular tissues, paranasal sinuses or brain.
  • Very rarely metastasize to regional lymph nodes, salivary glands or beyond - often slow to occur.
  • Carcinoma in situ (corneal form) is rarest.

Timecourse

  • Variable.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed Papers

Other sources of information

  • Roberts S M (2009) Ocular neoplasia. In: Large animal internal medicine. Eds: Smith P. Mosby Elsevier, St Louis. pp 1299-1305.


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