A case report: Variation in thyrotropin (TSH) secretion and isoforms in vivo and in vitro in a TSH-secreting pituitary adenoma

Neurosurgery is still the first step in the treatment of thyrotropin (TSH)- secreting pituitary adenomas, although new perspectives are emerging from m edical treatment with somatostatin analogs. We report the results of treatm ent with slow-release lanreotide in a woman who had undergone partial adeno mectomy for a supposedly non-secreting pituitary adenoma, which proved to b e a TSH-secreting adenoma, The treatment was effective in decreasing TSH an d free thyroid hormone levels. Because TSH has an oligosaccharide structure , we also analyzed TSH isoform profiles before and during slow-release lanr eotide treatment; this revealed a shift to a more acidic isoform profile, s imilar to that observed in healthy controls. Slow-release lanreotide treatm ent seems able to modify quantitative and qualitative TSH secretion.