Endocrine Abstracts

Introduction: Thyrotropin-secreting pituitary tumors (TSH-omas) are a rare cause of hyperthyroidism and account for 0.5 to 3 percent of all functioning pituitary tumors and much less than 1 percent of all cases of hyperthyroidism. The co-secretion of thyrotropin (TSH) and growth hormone (GH) in pituitary adenoma is extremely rare. Only a few cases have been reported.

Observation: We report the case of a 40-year-old man who consulted an ophthalmologist for headache, and left monocular temporal hemianopia. A brain MRI revealed a 3 cm pituitary macroadenoma with an opto-chiasmatic impact. In front of this adenoma, a hormonal pituitary assessment showed a central hyperthyroidism with a high TSH level at 6.83 mUI/l and a high FT4 level at 42 ng/l, a co-secretion of growth hormone; GH level at 4.2 ng/ml, IGF1 level at 268,27 ng/mL and a failure of GH suppression at the oral glucose tolerance test, a gonadotropic insufficiency; FSH 0.9 UI/l, LH 1.2 UI/l, Testosterone 0.57 ng/ml, a reassuring cortisol level at 430 nmol/l and a normal prolactin level at 30 ng/mL. The patient was put under antithyroid drugs and referred to a neurosurgical center for a surgical treatment.

Conclusion: TSH-omas with associated hypersecretion of other pituitary hormones are found in 24.8% of cases. Hypersecretion of GH, resulting in acromegaly, is one of the most frequent associations (15.1%) along with prolactin secretion (8.4%). This may be explained by the fact that somatotroph and lactotroph cells share with thyrotropes common transcription factors. Surgery remain the usual first line of therapy, and further treatment by radiotherapy or somatostatin analogue is discussed case by case.