Reversibility of thyrotroph hyperplasia after L-thyroxine replacement therapy in patients with juvenile primary hypothyroidism

Thyrotroph cell hyperplasia in primary hypothyroidism though well described is often not discussed as it remains clinically silent. This hyperplasia in long standing juvenile primary hypothyroidism presenting as 'pituitary tumor' is very uncommon. We report four patients with juvenile primary hypothyroidism, who were detected to have sellar/suprasellar masses on imaging performed for unrelated symptoms, and complete resolution in three of them after L-thyroxine replacement therapy.