Asymptomatic Thyrotropin-secreting Pituitary Macroadenoma in a Thirteen Year-old Girl: Successful First-line Treatment with Somatostatin Analogues

Background: Thyrotropin-secreting pituitary adenomas (TSHomas) are an extremely rare cause of hyperthyroidism. Up to now there are only few cases reported in pediatric age: the first therapeutic option is surgical resection, whereas medical treatment with somatostatin analogues has been reported only in cases wherein surgery was unsuccessful. Patient Findings: A 13-year-old girl was referred to our clinic for incidental finding of increased circulating free thyroid hormones in the presence of detectable TSH concentrations. She had no signs/symptoms of thyrotoxicosis. Resistance to thyroid hormone was excluded due to the lack of TSH response after TRH stimulation test. Cerebral magnetic resonance imaging showed the presence of a large pituitary macroadenoma, with intra- and supra-sellar extension. We decided to treat this patient with somatostatin analogue as first line therapy because of high surgery risks due to the tumor dimensions. The response to medical treatment was excellent, with rapid and significant tumor shrinkage. No major side effects were reported. Summary: We report the first pediatric case of TSHoma treated with somatostatin analogue as a first line therapy. The diagnosis was challenging because of the insidious and asymptomatic presentation of the tumor. Conclusions: We conclude that somatostatin analogues should be considered as first choice, bridge-to-surgery treatment in young patients, in order to reduce neurosurgical complications and prevent hypopituitarism during pubertal development