Incidental Detection of Occult Thyroid Carcinoma with ¹¹C-Choline PET/CT for High Risk Prostate Cancer

We report a case of a 65-year-old male patient with high-risk prostate cancer, re-staged with ¹¹C-choline positron emission tomography/computed tomography (PET/CT) for prostate specific antigen recurrences 3 years after radical prostatectomy and adjuvant radiation therapy. In addition to 2 suspicious presacral lymph nodes which were resected and proven to be metastatic, PET/CT revealed a very high uptake in a calcified thyroid nodule. Evaluation with fine needle aspiration was suspicious for thyroid carcinoma and the patient underwent total thyroidectomy, confirming a non-metastatic encapsulated follicular variant of papillary thyroid carcinoma. To our knowledge, this is the first report of a thyroid cancer diagnosed with ¹¹C-choline PET/CT for prostate cancer staging.