Characterization of an incipient granulosa cell tumour in a Holstein cow: Steroid hormone receptors and coregulators expression.

The objective of this study was to describe a case of a granulosa cell tumour (GCT) of incipient formation and to characterize it by its immunohistochemical pattern and hormonal profile. The case presented corresponds to a 7-year-old Holstein cow without reproductive disorders. No alterations were observed at rectal palpation, neither in the ultrasonography nor in the hormonal profile. A GCT concomitant with normal follicular development was diagnosed. Through a panel of immunohistochemical markers, a highly differentiated pattern could be determined in the GCT, which preserves the expression of steroid receptors (ESR1, ESR2 and PR) typical of granulosa cells, but does not express the enzymes for the synthesis of androgens (CYP17A1) and oestrogens (CYP19A1). In addition, the expression of co-regulators of steroid hormone receptors and neuroendocrine markers was described for the first time in a GCT in cattle. These results increase the information about GCTs in cattle before the ovarian function is compromised.