Endocrine Abstracts

JOINT1227

Background: Gallium-68 DOTA-TATE PET/CT is a widely utilized imaging modality for neuroendocrine tumors (NETs) due to its sensitivity for somatostatin receptors (SSTRs). However, incidental uptake in the thyroid is increasingly noted, raising questions about its clinical significance. This study analyzes ultrasonographic and clinicopathological features of patients with thyroid Ga-68 DOTA-TATE uptake.

Methods: This retrospective study included 39 patients who underwent Ga-68 DOTA-TATE PET/CT imaging from April 2019 to November 2023, exhibiting thyroid uptake categorized as focal, diffuse, or heterogeneous. Ultrasonographic evaluations, fine-needle aspiration biopsies (FNAB), and laboratory tests, including thyroid function and autoimmune markers, were reviewed. Statistical analyses assessed relationships between uptake patterns, SUVmax, and clinical parameters.

Results: Focal uptake was noted in 59% of patients, diffuse in 17.9%, and heterogeneous in 23.1%. Focal Ga-68 DOTA-TATE uptake in the thyroid gland remains a potential indicator of malignancy. Although no cases of carcinoma were confirmed in this cohort, the observed focal uptake emphasizes the importance of vigilant follow-up and thorough diagnostic evaluations such as ultrasonography and FNAB. FNAB was performed on 82% of patients with suspicious nodules; 33.3% yielded non-diagnostic Results Diffuse uptake correlated with benign conditions like Hashimoto’s thyroiditis. The mean SUVmax was 7.35 ± 3.08.

Ultrasonographic Findings: 87.2% of patients had nodular or multinodular goiter. Of these, 20.5% showed chronic thyroiditis. Mixed nodule structure predominated (68.6%), and 48.6% exhibited isoechoic patterns. FNAB results were benign in 46.7% and atypia of undetermined significance (AUS) in 17.8%, with one case identified as follicular neoplasm.

Discussion: Focal Ga-68 DOTA-TATE uptake in the thyroid may signify malignancy risk, underscoring the need for systematic evaluation. Diffuse uptake aligns more commonly with benign thyroid diseases, particularly autoimmune conditions. An inverse relationship between SUVmax and BMI hints at metabolic and inflammatory influences on SSTR expression. High non-diagnostic FNAB rates indicate challenges in conclusive diagnoses, warranting further studies.

Conclusion: Focal Ga-68 DOTA-TATE uptake is a potential marker of malignancy, while diffuse uptake often suggests benign pathology. Comprehensive diagnostic approaches, including ultrasonography and FNAB, are critical for incidental thyroid findings on Ga-68 DOTA-TATE PET/CT imaging. Further research on SUVmax correlations with metabolic factors is needed to refine patient management strategies.