Ovarian cancer. Coloured computed tomography (CT) scan of the abdomen of an 87 year old female with a large granulosa cell tumour (GCT, centre) in her ovary. GCT is a rare cancer arising from granulosa cell tissue, a hormonally active component of the ovarian tissue that is responsible for estradiol (female sex hormone) production. Granulosa cell tumours of the ovary are considered low grade malignancies with a relatively more favourable prognosis than other much more commonly encountered epithelial ovarian tumours.