[Thyrotropin-secreting adenomas of the hypophysis]

Thyrotropin secreting pituitary adenomas are scarce. They may cause an extremely rare form of hyperthyroidism. The diagnosis is often delayed because the clinical symptoms are attributed to common types of hyperthyroidism. The diagnosis involves detection of elevated or normal (unsuppressed) thyrotropin levels in hyperthyroid patients and evidence of a pituitary adenoma by computed tomography or magnetic resonance imaging. The thyrotropin response in the thyrotropin-releasing hormone test is either absent or insufficient. When the pituitary microadenoma appears to be undetectable, the familiar syndrome of selective pituitary resistance to thyroid hormones has to be excluded. Treatment involves extirpation of the tumour. If the macroadenoma is not removed completely, external radiotherapy of the pituitary follows. If this conventional treatment does not produce an adequate effect, treatment with long-acting somatostatin analogues is recommended.