Primary hypothyroidism presenting as growth delay and pituitary enlargement.

We report the case of a young boy being considered for pituitary surgery because of pituitary enlargement found during assessment of growth delay. There was no goitre but he was hypothyroid clinically and biochemically. The finding of an elevated TSH suggested primary thyroid disease with thyrotroph hyperplasia. Treatment with L-thyroxine resulted in prompt resolution of his pituitary enlargement and improvement in his visual fields.