Asymptomatic thyrotropin-secreting pituitary macroadenoma in a 13-year-old girl: Successful first-line treatment with somatostatin analogs

Background: Thyrotropin-secreting pituitary adenomas (TSHomas) are an extremely rare cause of hyperthyroidism. Up to now there are only few cases reported in the pediatric age range. Thefirst therapeutic option is surgical resection, whereas medical treatment with somatostatin analogs 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 thyrotropin-releasing hormone (TRH) stimulation test. Cerebral magnetic resonance imaging showed the presence of a large pituitary macroadenoma, with intra-and suprasellar extension. We decided to treat this patient with somatostatin analog as a 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. The patient developed central hypothyroidism that was corrected with L-thyroxine therapy. Summary: We report the first pediatric case of TSHoma treated with somatostatin analog as a first-line therapy. The diagnosis was challenging because of the insidious and asymptomatic presentation of the tumor. Conclusions: We conclude that somatostatin analogs 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.