[Malignant ovarian tumour as cause of virilisation in a 12 year-old girl].

Virilisation in girls includes androgen dependent growth of terminal hair, acne, deepening of the voice and increased muscle mass. Sudden onset of symptoms, rapid progression, short duration and hyperandrogenaemia are ominous signs and the patient must be referred to a specialist as soon as possible to rule out cancer and avoid worsening of the irreversible virilisation. We describe a girl with severe virilisation as the sole symptom of an androgen producing Sertoli-Leydig cell tumour. Ovarian tumours are rare in children and malignant ovarian tumours account for less than 1% of childhood cancer.