Fig. 1

Upper panel: dynamic changes in brain and bone metastases. Hemorrhagic brain metastasis over the right occipital area was detected by brain MRI (16th month) (A-1); strong radioiodine uptake over the metastatic brain lesion was demonstrated by radioiodine whole body scan (18th month) (A-2); significant shrinkage (2.5 to 1.3 cm) of the brain metastasis after radioiodine, external beam radiation, and lenvatinib therapy, shown by brain MRI (29th month) (A-3); persistent regression of the metastatic brain lesion (39th month) (A-4). Disease progression with multiple bone metastasis was detected by 18 FDG-PET PET scan (43th month) to the right manubrium of the sternum (B-1), thoracic T4–5 spine (B-2), right ischium (B-3), and right iliac (B-4). Lower panel: the dynamic changes of serum TSH and thyroglobulin in response to various treatment modalities. The number indicates the TSH-dependent serum thyroglobulin level (ng/mL)