# Corneal Epithelial and Vascular Tumors in Domestic Species: Narrative Review of the Literature and Insights from New Cases (2016–2025)

## TL;DR

This paper reviews corneal tumors in dogs, cats, and horses, finding a link between brachycephalic dogs and a specific cancer type and noting common complications in cats.

## Contribution

The study adds 94 new cases to the literature, revealing species-specific associations and complications of corneal tumors.

## Key findings

- Brachycephalic dogs are strongly associated with corneal squamous-cell carcinoma.
- Cats frequently experience symblepharon and corneal perforation alongside corneal tumors.
- Most corneal tumor studies in animals are case reports, highlighting a need for more comprehensive research.

## Abstract

Corneal neoplasms are rare in all species. Squamous-cell carcinoma and vascular tumors are the most frequently reported, with distinct etiopathogenesis across species. The present study reviews the current literature and describes 94 new cases (in dogs, cats, and horses) from our archives, aiming to contribute to current knowledge on corneal vascular and epithelial neoplasms in domestic animals. The combined results highlighted a strong association between brachycephalic dogs and c-SCC occurrence, and the frequent coexistence of symblepharon and corneal perforation with corneal tumors in cats.

Neoplasia of the cornea is overall rare, with corneal squamous-cell carcinoma (c-SCC) being most commonly reported in all species. C-SCC pathogenesis has been related to UV exposure in humans and horses, and to papillomavirus infection in humans. In dogs, brachycephalic conformation and chronic keratitis were associated with c-SCC. Corneal vascular tumors have also been exceptionally reported in humans, and rarely in animals. In dogs, they have been suggested to be UV-related. Except for equine c-SCCs, most studies on corneal neoplasms are case reports. The present study aimed to review the literature on epithelial and vascular corneal tumors in dogs, cats, and horses, adding new cases from our archives. Pubmed and Web of Science were searched (1980–2025) using the following keywords: cornea, neoplasia, carcinoma, hemangioma, hemangiosarcoma, dog, cat, and horse. Additionally, 94 new cases of corneal neoplasia were retrieved: 47 dogs (40 epithelial and seven vascular); 29 cats (14 epithelial and 15 vascular) and 18 horses. Signalment, clinical history, and histopathological characteristics were analyzed and compared with the literature. The combined results supported a strong association between brachycephalic dogs and c-SCC occurrence and highlighted the frequent coexistence in the feline species of symblepharon and corneal perforation, with corneal tumors.