Lacrimal Gland Adenoma in a Sheep

The lacrimal gland is a diamond-shaped, tubuloalveolar gland that secretes the serous component of tears. A four-year-old female crossbreed sheep suffering from left eye protrusion was referred to a Veterinary Hospital. Ophthalmic examination revealed epiphora, superficial ulcerative keratitis, corneal edema and neovascularisation. Moreover, ultrasound examination showed a large heterogeneous mass with variable reflectivity in the intraconal and extraconal spaces. Grossly, a 2.5×1.5×0.5 cm oval firm grayish mass was observed. Histopathologically, the mass was composed mainly by tubules with two cell types including cuboidal luminal epithelial cells and peripheral myoepithelial cells. The tubular structures were separated by proliferating myoepithelial cells. Mitotic figures, cellular pleomorphism and atypia were not seen. Immunohistochemically, most of the luminal epithelial cells showed an immunopositive reaction with a cytokeratin (AE1/AE3) marker. On the basis of these findings, the mass was diagnosed as a lacrimal gland adenoma.