Excellent Response to Multimodal Therapy Approach in Hyperfunctioning Metastatic Follicular Thyroid Carcinoma Diagnosed on 123I-SPECT/Ultrasound Fusion Imaging

An 83-year-old woman presented with new-onset hyperthyroidism and suspicious thyroid nodules on ultrasound (US). Conventional 99mTcO4 thyroid scintigraphy showed hyperfunctioning areas that could not be clearly assigned to the US findings. With the aid of 123I-SPECT/US fusion imaging, suspicious nodules were unambiguously identified as autonomously hyperfunctioning lesions. Additional 123I whole-body scan revealed iodine-avid lymphonodular and pulmonal metastases. Clinical diagnosis of hormone-active thyroid carcinoma was made and histologically confirmed. Because of significant hyperthyroidism as well as multiple partially iodine-negative metastases, a multimodal treatment regime consisting of 131I radioiodine therapy, surgery, and radiation therapy was conducted, leading to almost complete remission.