Autonomously Functioning Thyroid Nodule With 99m Tc-PSMA Uptake in a Patient With Prostate Cancer.

We present the findings of a 99m Tc-PSMA scan in a 76-year-old man with a history of prostate cancer. He was referred for re-staging and response to treatment. The 99m Tc-HYNIC PSMA scan incidentally detected an area of increased uptake in the neck region. Subsequent SPECT/CT imaging revealed a large, heterogeneous PSMA-avid thyroid nodule with macrocalcification, suggesting a benign thyroid nodule. Comprehensive imaging confirmed hyperthyroidism with a large autonomously functioning nodule. The case underscores the importance of recognizing PSMA uptake in benign thyroid lesions, emphasizing the need for a thorough evaluation to prevent misdiagnosis and ensure appropriate management.