Octreotide in the diagnosis and treatment of pituitary thyrotropin-secreting adenoma

Objective: To evaluate the efficacy of octreotide in the diagnosis and treatment of pituitary thyrotropin (TSH)-secreting adenoma.

Methods: A 34-year man presented with central hyperthyroidism and pituitary TSH-secreting macroadenoma was reported. (99 m)Tc-octreotide scan and magnetic resonance imaging were completed to make the location diagnosis of the adenoma. Octreotide in 0.1 mg dose was subcutaneously injected every 8 hours for 10 days. Serum TSH level and tumor size were observed and trans-sphenoidal adenoma resection was completed.

Results: Pituitary TSH-secreting adenoma displayed positive sign in (99 m)Tc-octreotide scan. Antithyroid drug was of no help in depressing thyroid function to normal. However, octreotide treatment could revert thyroid function to normal rapidly. A significant shrinkage of tumor mass from 3.0 cm x 2.0 cm x 2.5 cm to 2.0 cm x 2.0 cm x 1.5 cm was observed and a shrinkage of thyroid gland from III to II also observed.

Conclusions: (99 m)Tc-octreotide scan is one of the useful tools for location diagnosis of TSH-secreting adenoma. Octreotide can effectively control central hyperthyroid and make tumor shrink, and it can be a satisfactory method of preoperative preparation for TSH-secreting adenoma.