Endocrine Abstracts

TSH-secreting pituitary tumors (TSH-omas) are a rare cause of hyperthyroidism and account for < 1% of all pituitary adenomas. They are usually benign adenomas arising from a monoclonal expansion of neoplastic thyrotropes.

We report two patients’ cases with thyrotropinoma.

The first case is a 73-year-old woman, who presents a TSH-secreting pituitary adenoma in the setting of multiple endocrine neoplasia syndrome type 1 (TSH-omas and primary hyperparathyroidism). The patient had clinical thyrotoxicosis, diffuse goiter, elevated circulating levels of free tri-iodothyronine (FT₃) and free thyroxin (FT₄), and a non-suppressed basal serum TSH (TSH =6.53 μU/ml).

Magnetic resonance imaging (MRI) scan showed an invasive pituitary adenoma causing right cavernous sinus invasion compression, there was no evidence of optic chiasmal compression or stalk deviation. The tumor was diagnosed and treated at a late stage (8 years after the onset of hyperthyroidism). Because of comorbidities and the poor general condition in our patient’s case, surgical approach of the TSH-oma was contraindicated and pituitary radiotherapy was considered.

The second case is about a 46-year-old woman presented with symptoms of acromegaly and thyrotoxicosis. A large macroadenoma of the pituitary gland was diagnosed by magnetic resonance imaging (MRI) scan. Peripheral thyroid hormone was elevated but TSH remained in the normal range (TSH=3.2 μUI/ml). GH levels were elevated and remained high after oral glucose tolerance test.

GH/TSH – secreting pituitary tumor (TSH and GH-oma) was diagnosed and transsphenoidal adenomectomy was performed.

We report two new cases of TSH secreting pituitary adenomas. The first patient had a TSH-secreting pituitary adenoma in the setting of multiple endocrine neoplasia syndrome. The second case is particular by its association with an acromegaly.