Clinicopathological and immunohistochemical characteristics of ovarian luteoma associated with endometrial hyperplasia in a bitch.

In the present study, a rare case of ovarian luteoma is described in a 5-year-old German Shepherd dog. Histopathologically, the tissue sections composed of multiple lobules of polyhedral cells with abundant, finely vacuolated cytoplasm, centrally located nuclei surrounded by fine well-vascularized connective tissue. Neoplastic cells showed strong cytoplasmic positivity for inhibin-α and vimentin and moderate for calretinin. Based on histopathological and immunohistochemical findings, the tumor was diagnosed as ovarian luteoma. [ABSTRACT FROM AUTHOR]