Granulosa cell versus Sertoli-Leydig cell tumours

Sex cord stromal tumours of the ovary arise from the granulosa and theca cells, which support and nourish the egg, as well as from Sertoli and Leydig cell types. Because these cells normally make sex hormones, the tumours often keep doing so, and hormone production is their characteristic feature. The hormone effect is sometimes the first sign that a tumour is there.

A granulosa cell tumour is the commonest oestrogen-secreting tumour of the ovary. Oestrogen drives growth of the endometrium (the lining of the womb). Normally progesterone balances that effect, so oestrogen acting without it is called unopposed oestrogen. The lining then thickens, giving endometrial hyperplasia (overgrowth of the womb lining) and irregular bleeding, and prolonged exposure can progress to endometrial cancer. In the tumour tissue, the classic clue is Call-Exner bodies: small follicle-like spaces with a central pink core. A follicle is the fluid-filled sac that holds each developing egg.

A Sertoli-Leydig cell tumour is a rare tumour from the same group, and it usually affects one ovary. Its cells mostly make androgens (male-type sex hormones such as testosterone). Excess androgen causes virilisation, the development of male features such as a deepening voice and hirsutism (excess male-pattern hair growth). It often disturbs the menstrual cycle too, so periods may stop.

Think of a granulosa cell tumour when an ovarian mass comes with an overgrown womb lining or abnormal bleeding; virilisation points to a Sertoli-Leydig cell tumour instead.