Thyroid stimulating hormone secreting tumor

Thyroid stimulating hormone (TSH)-secreting pituitary adenomas (TSH-omas) are rare disorders causing central hyperthyroidism, a condition characterized by high levels of free thyroxin (T4) and free triiodothyronine (T3) in the presence of measurable TSH concentrations. Failure to identify the presence of TSH-omas may result in an improper thyroid ablation which may lead to a significant increase of tumor mass. The diagnosis is mainly achieved by measuring TSH after T3 suppression and TRH stimulation tests, these dynamic tests being useful in distinguishing TSH-omas from syndromes of resistance to thyroid hormone action (RTH). The treatment of choice is surgery. If surgery fails, somatostatin analogs have been found to be effective in normalizing TSH secretion in more than 90% of patients.