Morphological Description of Three Rare Canine Intraocular Tumours

Introduction Tumours of glial and neuroepithelial origin (except for iridociliary adenomas) are rare intraocular neoplasms in dogs. Morphological and immunohistochemical features of three intraocular neoplasms are presented and categorized according to the current WHO classification. Materials and Methods Case 1: the eye of a golden retriever with a 0.5 cm mass adherent to the optic disc. Case 2: a Labrador retriever with a 1.5 × 1 × 0.5 cm neoplasm expanding the ciliary body. Case 3: a German shepherd dog with a 0.6 cm retinal mass near the ora serrata. Results The tumour from case 1 consisted of densely arranged polygonal cells forming few rosette-like structures with intraocular spreading. The tumour from case 2 was composed of polygonal and spindle cells embedded in expanded chondroid areas. The retina was focally expanded by the neoplasm. The tumour from case 3 was mainly composed of spindle cells. Various immunohistochemical markers (vimentin, GFAP, S-100, neurofilament) were applied. Conclusions On the basis of the microscopical and immunohistochemical features, a medulloepithelioma was diagnosed in case 1, a benign teratoid medulloepithelioma in case 2 and a glioma (astrocytoma) in case 3.