Long-standing benign granulosa-theca cell tumour in a cow

Ovarian tumours have been poorly investigated in living cattle. In a 6 -year-old Holstein cow with irregular heats, an enlarged left ovary was found with a multicystic structure at ultrasound. A granulosa-theca cell tumour (GTCT) was diagnosed by the detection of increased circulating levels of 17 -beta oestradiol (E2), inhibin B (INH) and antimullerian hormone (AMH). The owner gave no consent for surgery and the cow produced milk for almost 2 years. At postmortem examination, the genital tract was examined. The neoplastic ovary had an impressive size (22x15x12cm); there was mucometra and marked thickness of cervix and vagina, interpreted as effects of the chronic E2 exposition. Histology confirmed the typical follicular pattern of a benign GTCT and neoplastic cells expressed INH alpha and AMH by immunohistochemistry. Chronic INH and AMH high levels caused the inactivity of the contralateral ovary, a common finding in long standing GTCTs.