Peer-reviewed veterinary case report
Malignant medulloepithelioma of the optic nerve in a horse.
- Journal:
- Veterinary pathology
- Year:
- 1978
- Authors:
- Eagle, R C et al.
- Species:
- horse
Plain-English summary
An 18-month-old Standardbred filly was found to have a large tumor in her eye that was affecting her optic nerve. This tumor was identified as a malignant medulloepithelioma, which is a rare type of cancer that starts from certain cells in the eye. The tumor was examined under a microscope, revealing unusual cell structures. This case is notable because it's the first time this type of tumor has been reported in a horse's optic nerve. When a horse has an eye mass and cannot perceive light, it may indicate that the optic nerve is seriously involved, and in such cases, a portion of the optic nerve may need to be surgically removed.
Abstract
An 18-month-old Standardbred filly had a large intraocular tumor involving the optic nerve. The tumor was a malignant medulloepithelioma, a rare intraocular neoplasm derived from the primitive medullary epithelium. By light microscopy the tumor had cords and lobules of primitive neuroepithelial cells that formed clefts and true rosettes. Electron microscopy of the rosettes showed a girdle of zonulae adherentes joining the apices of the cells as well as several basal bodies. This is the sixth report of equine intraocular medulloepithelioma, and, to the best of our knowledge, the first intraocular medulloepithelioma arising from the optic nerve head in a horse. Massive involvement of the optic nerve should be suspected when an eye containing an intraocular mass in the posterior segment lacks light perception. In such cases a long segment of opitc nerve should be resected.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/695223/