Precocious breast development: a case of unilateral hyperplasia of the adrenal cortex.

The case of a 14-month-old girl presenting with precocious breast development due to adrenal hyperplasia is reported. The endocrine studies revealed a slight elevation of the plasma progesterone, 17 alpha-hydroxyprogesterone, testosterone and oestrone levels, and an increased urinary oestrogen excretion. The findings of the ultrasound examination and the evidence that the oestradiol concentration in the left adrenal vein was higher than in the right adrenal vein confirmed the diagnosis of left adrenal hyperfunction. Surgical exploration revealed unilateral hyperplasia of the adrenal cortex. After adrenalectomy the plasma hormone levels and urinary oestrogen excretion fell to normal, with concomitant regression of breast tissue. The girl shows no signs of recurrence of the disorder in a 2 year follow-up. This adrenal hyperplasia might be a benign adrenal disorder causing precocious breast development.