Coincidence of meibomian adenoma and squamous cell carcinoma in the upper eyelid of a sheep: histopathological and immunohistochemical studies

This report is related to a female 7-year-old crossbreed sheep whose right eye had been protruded and swelling of upper eyelid was observed. Routine enucleating was performed. Histopathological evaluation of eyelid revealed coincidence of two kinds of neoplasms. The first part was composed of multiple lobules of sebocytes, which were detected as meibomian adenoma. The second section included infiltrating islands of neoplastic squamous epithelium extending through the basal lamina of the epithelium with keratin pearls and was noted as grade I squamous cell carcinoma. Immunohistochemical study of cytokeratin showed positive reaction in both kinds of neoplastic cells. This is a rare case of meibomian adenoma in sheep with squamous cell carcinoma coincidence.