Diffuse pulmonary metastases with negative ¹⁸FDG positron emission tomography/computed tomography and positive post-radioiodine therapy scan of papillary thyroid cancer.

A female papillary thyroid cancer patient with diffuse micronodular pulmonary metastases was confirmed only by post radioactive iodine (RAI) therapy whole body scan (RxWBS). Her diagnostic iodine-131 whole body scan (DxWBS), chest CT and 18FDG PET/CT scan were all negative. Attention and pitfalls of this case concerning surgical and RAI dose management are against current international guidelines on thyroid cancer.