Thyrotropin-secreting microadenoma and the importance of a prompt diagnosis: A case report.

Background: The prevalence of thyrotropin-secreting pituitary adenomas, most being macroadenomas, is one to two cases per million inhabitants. Their differential diagnosis may be challenging, especially for microadenomas.

Case description: We present the case of a 50-year-old male with progressive neck enlargement, hot sudorific hands, anorexia, diarrhea, and weight loss over the preceding three months. Laboratory evaluation revealed high thyroid hormones, predominantly high free triiodothyronine of 7.74 pg/mL (reference range 2.3-4.2), with a non-suppressed thyroid stimulating hormone (TSH) of 1.73 µIU/mL (reference range 0.55-4.78). A high level of suspicion directed additional evaluation that revealed a high total alpha-subunit of glycoprotein hormones (αGS) and αGS/TSH ratio. Magnetic resonance imaging revealed a six mm pituitary lesion. A microthyrotropinoma was diagnosed, and long-acting octreotide was initiated before surgery for symptomatic control. Endoscopic transnasal transsphenoidal tumor resection was performed months later. The patient was in remission one year after surgery with no pituitary deficits.

Conclusions: Reaching an accurate diagnosis on time is crucial for deciding the optimal therapeutic approach and preventing and decreasing the frequency of endocrine and neurological complications. HIPPOKRATIA 2022, 26 (4):157-160.