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Bilateral ocular metastatic melanoma of unknown primary (MUP) in a dog
  1. Charlotte E Swain1,
  2. Rachel Pittaway1,
  3. Nicholas P Ilchyshyn1,
  4. Ben Blacklock2 and
  5. Renata Stavinohova3
  1. 1Pathology Service, Dick White Referrals, Six Mile Bottom, UK
  2. 2Ophthalmology Service, Royal Dick School of Veterinary Studies, Midlothian, UK
  3. 3Opthalmology Service, Dick White Referrals, Six Mile Bottom, UK
  1. Correspondence to Dr Charlotte E Swain; cswain2{at}


An 11-year-old Labrador retriever was evaluated for bilateral ocular discomfort and visual deficits. Ophthalmic examination revealed bilateral uveitis with secondary glaucoma; the right eye was blind. Further investigations revealed bilateral retinal detachment, a diffuse interstitial lung pattern and bilateral focal adrenomegaly. Aqueocentesis of the left eye diagnosed a melanocytic malignancy, whereas only inflammation was detected in the right eye. A staged bilateral enucleation was performed and histopathology revealed metastatic melanoma in both eyes. Complete staging diagnosed an unrelated pulmonary neoplasm but failed to detect a primary site of the melanoma. The patient was euthanased 17 weeks post diagnosis due to development of neurological signs. Postmortem examination confirmed disseminated melanoma but failed to reveal a primary site. This unusual case highlights the diagnostic utility of bilateral aqueocentesis in canine uveitis investigation and the critical role of histopathological evaluation of enucleated globes to discriminate between primary and metastatic neoplasia in the eye.

  • uveitis
  • glaucoma
  • melanoma of unknown primary
  • aqueocentesis
  • ocular histology
  • metastasis
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  • Contributors CES prepared the original draft of the manuscript. RS led the clinical management of the case, its diagnostics and treatment, and conceptualised the manuscript. NPI performed the cytology and provided the figure. RP performed the ocular histopathology and provided the figure. RS, RP and NPI assisted substantially in the editing of the manuscript. All authors reviewed the final manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement There are no data in this work.

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