Incidental Detection of Prostatic Lesion on 18 F-FDG PET/CT and 68 Ga-PSMA-11 PET/CT Leading to Diagnosis of Second Primary Prostatic Adenocarcinoma in a Patient of Differentiated Thyroid Cancer.

Second primary malignancies are being increasingly detected in the setting of thyroid cancer, because of adoption of the advanced imaging modalities including PET/CT. Herein, we present a patient of papillary thyroid carcinoma who initially underwent total thyroidectomy with bilateral neck dissection followed by 131 I radioactive iodine therapy. A prostatic lesion was incidentally detected on 18 F-FDG PET/CT scan, which was intensely 18 F-FDG avid and also showed intense focal 68 Ga-prostate-specific membrane antigen (PSMA) uptake on 68 Ga-PSMA-11 PET/CT scan. This led to the diagnosis of prostatic adenocarcinoma as a second primary cancer in this patient with papillary thyroid carcinoma.