[Thyrotropin-producing adenoma of the hypophysis]

A patient with a thyrotropin (TSH) secreting pituitary adenoma had hyperthyroidism with high levels of thyroid hormones and inadequate TSH secretion. After the challenge with thyrotropin releasing hormone (TRH), TSH level did not change. The normalization of plasma levels of thyroid hormones with antithyroid drugs was followed by an important increase in TSH levels. The adenoma was resected by the transphenoidal route and the diagnosis was confirmed by immunohistochemical study. Inadequate TSH secretion persisted after surgery, and radiation therapy with lineal accelerator was attempted. At present, one year after radiation therapy, inadequate TSH secretion requiring antithyroid drugs persists. We describe this clinical picture and briefly discuss the literature.