Severe untreated hypothyroidism in boys and girls may be associated with incomplete sexual precocity. Levels of plasma prolactin are elevated in primary hypothyroidism, and galactorrhea may be demonstrable more commonly in girls than in boys. Growth is impaired in these patients as in any child with hypothyroidism so there is no pubertal growth spurt. Girls may manifest breast development, menstrual flow and oestrogen effects on the vaginal mucosa, while the size of the testes increases in boys due to enlargement of the seminiferous tubules.
The pituitary gland may enlarge and erode the sella turcica due to increased TSH secretion and thyrotroph hyperplasia, thereby mimicking a tumour. Once the hypothyroidism is treated, sexual precocity reverts, and the sella turcica will decrease in size.
