[Functional activity of autonomous adenoma in Germany]

Area of Science:

• Endocrinology
• Nuclear Medicine

Background:

• Current guidelines recommend thyroid scintiscans for suspected autonomy only with low or suppressed TSH.
• Ultrasound-guided fine-needle biopsy is often the next step for nodules >1.0 cm with normal TSH, bypassing scintiscan.
• Limited data exists on TSH levels in German patients with autonomous adenomas.

Purpose of the Study:

• To evaluate the incidence of reduced or suppressed TSH in autonomous adenomas >1.0 cm in a German cohort.
• To determine if normal TSH levels can exclude focal thyroid autonomy.
• To assess the diagnostic utility of TSH in identifying autonomous adenomas.

Main Methods:

• Prospective study of 496 patients with nodular goiter.
• Scintiscan screening to identify 100 autonomous adenomas >1.0 cm.
• Investigations included ultrasound, scintiscan, and laboratory tests (fT3, fT4, TSH, TPO-antibodies) with a TSH reference range of 0.4–4.0 µU/ml.

Main Results:

• Focal autonomy was present in 21% of patients with nodular goiter.
• Of the 100 autonomous adenomas, 32% had reduced or suppressed TSH (<0.4 µU/ml).
• A significant 68% of autonomous adenomas presented with normal TSH levels.

Conclusions:

• Autonomous adenomas are prevalent in Germany (21% of thyroid nodules), with most (68%) showing normal TSH.
• TSH levels do not reliably correlate with scintiscan-detected autonomous adenomas.
• Routine scintiscan for nodules >1.0 cm is recommended to prevent unnecessary fine-needle biopsies of autonomous adenomas.