Pituitary thyrotoxicosis presenting as abnormal thyroid function testing during pregnancy: a case report

BACKGROUND: Central hyperthyroidism is a rare form of hyperthyroidism caused by thyrotrope pituitary adenomas. It is characterized by elevated thyroid-stimulating hormone alongside high thyroxine and triiodothyronine. Goiter is the most common symptom of central hyperthyroidism. Surgical resection as well as somatostatin analog therapy typically achieve resolution of hyperthyroid symptoms and restoration of a euthyroid state. CASE PRESENTATION: We report the case of a 30-year-old primigravida Caucasian/White female who presented with abnormal thyroid function testing results and multinodular goiter during pregnancy. Postpartum, she was found to have multinodular goiter on physical examination as well as persistent elevated thyroid-stimulating hormone with elevated free thyroxine and free triiodothyronine. Magnetic resonance imaging disclosed a large pituitary macroadenoma, and she subsequently underwent resection of the mass. She achieved a sustained euthyroid state postoperatively. CONCLUSIONS: This case shows how central hyperthyroidism can present without the more apparent symptoms of thyrotoxicosis and that successful resolution of central hyperthyroidism may be achieved postoperatively.