The polycystic ovary syndrome (PCOS) is the commonest cause of hirsutism, menstrual irregularities and infertility. The diagnosis is based on classical ultrasound evidence of polycystic ovaries (10 or more cysts of less than 8 mm in diameter with increased dense stroma) and/or biochemical disturbances such as elevated LH level raised testosterone and/or androstenedione and decreased SHBG. Insulin resistance occurs in PCOS, irrespective of the degree of obesity. Hyperinsulinaemia has important effects on the clinical expression of the syndrome, influencing the severity of clinical signs of hyperandorgenism. Hirsutims, mild rather than marked, is present in over 70 per cent of women with PCOS, although both hirsute and non-hirsute patients with PCO have excessive amounts of male hormones in their blood.
Hyperthecosis is a rare condition characterised by diffuse luteinisation and hyperplasia of ovarian stroma. Plasma testosterone is often elevated, sometimes markedly, and the ovaries are bilaterally enlarged. The aetiology is unknown although it may represent a variant of PCOS.
Androgen-producing ovarian tumours such as arrhenoblastoma, hillus cell tumour, lipoid cell tumour, ovarian lipid cell tumour, luteoma of the pregnancy are extremely rare.