Endocrine Abstracts

Pituitary adenomas which co-secrete GH and TSH accounts for <0.2% of all adenomas of the pituitary. Symptoms of hypertyroidism are usually masked by clinical manifestations of acromegaly. Here, we have reported the result of the primary one year long medical therapy in a case who was diagnosed to have adenoma co-secreting GH and TSH.

Case: Seventy-years-old female patient has admitted with the complaints of excessive sweating, enlargement of hands and feet. In physical examination there were frontal bossing, coarsening of facial structures and acral enlargement. In hormone tests, GH level was: 17 ng/ml and IGF1 level was: 607 ng/ml (64–188 ng/ml). GH levels were not suppressed during glucose suppression test. Her serum TSH, fT₄ and fT₃ levels were elevated. Serum alpha subunit was also high (80 IU/l). In thyroid ultrasonography, we have detected goiter. In thyroid scintigraphy, homogenous diffuse hyperplasia of both lobes was reported. In pituitary MRI, a 13×16 mm sized macroadenoma on the left handside of the pitiutary gland. The diagnosis of acromegaly was made with high suspicion of TSH co-secretion from the adenoma. Since the patient had dilated cardiomyopathy and obstructive sleep apnea syndrome, the operation could not be done. Octreotide LAR was started in a dosage of 30 mg/28 days. The patient was evaluated at the first year of the therapy. IGF1 level decreased (285 ng/ml) and the size of the adenoma was reduced (11×10 mm). Serum fT₄, fT₃ and TSH levels were normal together with normalization of serum alpha subunit.

Conclusion: Coexistence of GH secreting adenoma and TSHoma is rare. In such cases, transsphenoidal surgery must be the first choice for therapy. However when operation is contraindicated as it occurred in our case or when the lesion cannot be excised completely resulting in residual mass, somatostatin analogues should be preferred as an alternative therapy.