Endocrine Abstracts

Introduction: Thyrotropin-producing adenomas (TSH-omas) constitute about 1% of pituitary adenomas. TSH-omas are a rare cause of hyperthyroidism. In conjunction with biochemical parameters and dynamic endocrine testing, image evaluation of the pituitary gland and sella turcica is mandatory for establishing a correct diagnosis. TSH-omas are usually large tumors and tend to be invasive. Greater amounts of invasion correlate with incomplete surgical removal of the tumor and, thus, continued hormonal secretion. Therefore, an early diagnosis and a complete surgical removal are essential.

Case report: A 29-year-old female was referred to the endocrinology outpatient unit because of a 5 months history of bilateral galactorrhea and amenorrhea. She also complained about symptoms of hyperthyroidism (13 Kg weight loss in 10 months, palpitations, hand tremors, heat intolerance and nervousness). On physical a grade I goiter was observed. Pituitary hormone levels were determined; abnormal values are shown in table 1 – the rest was normal. In order to rule out the thyroid hormone resistance syndrome, TRH testing and a MRI of the pituitary gland was performed. TRH testing was compatible with a TSH-oma (Basal TSH 7.63 μUI/mL; after 20 minutes 7.99 μUI/mL; after 60 minutes 6.97 μUI/mL). Pituitary MRI showed a macroadenoma.

The patient was started on a long-acting somatostatin analog (Octreotide) and is currently awaiting surgery.

Discussion: 1- Signs and symptoms of TSH-oma vary and are unspecific. Galactorrhea and amenorrhea are present in 30% of these patients.

2- In case of hyperthyroidism without TSH suppression and abnormal pituitary hormone values, a TSH producing pituitary adenoma should be suspected.