Leydig cell tumours represent more than 75% of all
testosterone-secreting ovarian masses. These benign tumours are frequently occult or very small, but cause dramatic
virilization. Chronic
hyperandrogenism can also induce systemic complications, which increase morbidity and mortality risk. One of the most obvious effects of increased
testosterone levels is
polycythemia, a complication which induces dermatologic, osteoarticular and gastrointestinal manifestations and is associated with increased thrombotic risk. However, scientific literature reports few data concerning etiopathogenesis and management of
polycythemia in patients with Leydig cell tumours. Moreover, no data are available about the effect of
androgen excess on other concomitant tumours expressing
androgen receptors. In this paper we report for the first time the case of a woman, with previous
infertility, dramatic virilisation and chronic
erythrocytosis, who was affected by an occult Leydig cell tumour and an
androgen receptor positive
breast cancer. This association gives us the opportunity to discuss the role of the
steroid receptor expression of
breast cancer in the presence of circulating
androgen excess. Moreover, we demonstrate for the first time that treatment with
flutamide (anti-
androgen drug) is able to normalize blood cell count and haematocrit, before of achieving the definitive cure of
hyperandrogenism by
oophorectomy.