Ectopic adrenal tissue has been reported to occur in equine ovaries and testes, more frequently in stressed, ill, or pregnant animals. In this study, the presence and endocrine activity of ectopic adrenal tissue in equine gonads was investigated. In 278 pairs of ovaries and 100 pairs of testes, the anomaly was observed with a comparable prevalence of 6%-9%; the tissue appeared as nodules, found on the ovarian surface and in the mediastinum. Microscopically, these usually appeared disorganized, with a tendency toward differentiation into the zonae in larger nodules. The endocrine activity of the large ectopic nodules was demonstrated by the extraction of 17-β estradiol (1.1 ng/g), progesterone (12.4 ng/g), testosterone (11.3 ng/g), and cortisol (814.8 ng/g), but in none of the cases was gonadal function apparently influenced.

Ectopic adrenal tissue has been reported to occur in equine ovaries and testes, more frequently in stressed, ill, or pregnant animals. In this study, the presence and endocrine activity of ectopic adrenal tissue in equine gonads was investigated. In 278 pairs of ovaries and 100 pairs of testes, the anomaly was observed with a comparable prevalence of 6%-9%; the tissue appeared as nodules, found on the ovarian surface and in the mediastinum. Microscopically, these usually appeared disorganized, with a tendency toward differentiation into the zonae in larger nodules. The endocrine activity of the large ectopic nodules was demonstrated by the extraction of 17-β estradiol (1.1 ng/g), progesterone (12.4 ng/g), testosterone (11.3 ng/g), and cortisol (814.8 ng/g), but in none of the cases was gonadal function apparently influenced.