(A309) PET-PSMA as a marker for Papillary Thyroid Carcinoma: a case report.

Introduction: We present the case of a 44-year-old male patient with a thyroid incidentaloma detected via PET-PSMA during evaluation for prostate adenocarcinoma in a second-level hospital in Mexico.

Methods: A thyroid incidentaloma is an unexpected thyroid lesion detected through imaging performed for unrelated conditions. Prostate-specific membrane antigen (PSMA), encoded by the FOLH1 gene on chromosome 11, is expressed in tissues such as the prostate, kidneys, and salivary glands and serves as a diagnostic marker, primarily for prostate cancer. Recent findings suggest PSMA expression in thyroid cancer microvasculature. (1)
The patient underwent PET-PSMA on November 3, 2023, revealing a thyroid nodule in the right lobe. A neck ultrasound identified two nodules, the largest measuring 0.7 × 0.6 cm, classified as TIRADS 3 and 4. Fine-needle aspiration confirmed papillary thyroid carcinoma, prompting a total thyroidectomy on January 19, 2024. Pathology confirmed carcinoma in the right lobe with clear margins.

Results: A systematic diagnostic protocol is essential for incidental thyroid lesions. PET-PSMA has potential as a complementary tool for detecting malignancies beyond prostate cancer, including renal cell carcinoma, hepatocellular carcinoma, breast cancer, lung cancer, and thyroid cancer. Its use alongside PET-FDG may improve lesion visualization and diagnostic accuracy. (2)

Conclusions: This case highlights PET-PSMA’s role in identifying occult thyroid malignancies. While promising, further studies are required to evaluate its clinical utility, given the lack of radiotracers with adequate sensitivity and specificity for thyroid cancer.