The regulation of complex synergistic hormonal interrelationships in normal human breast development is not well understood. Appropriate development involves the interplay of hypothalamic, pituitary, and target organ hormones. A 14-year-old girl is described who developed massive virginal breast hypertrophy immediately after the onset of menarche and several months following a severe blow to the head.
Initial endocrine studies revealed low serum hormonal iodine, decreased thyroid uptake of sodium iodide I 131, normal thyroid stimulating hormone, and an exaggerated growth hormone response following arginine infusion. Urinary follicle stimulating hormone was absent and there was no estrin effect demonstrable in a maturation index of vaginal cytology. Although precocious puberty, gynecomastia, and galactorrhea have been described previously following hypothyroidism secondary to thyroiditis and enlargement of the sella turcica, no previous patients have been reported with massive breast hypertrophy and mild hypothyroidism.