Fig. 2.

A 46-year-old female patient underwent rib excision for an incidentally found rib mass and was diagnosed as having metastatic thyroid cancer. Subsequently, she underwent total thyroidectomy with central neck dissection, and the pathologic result was intrathyroidal microscopic papillary carcinoma with one central neck node metastasis (pT1N1aM1, stage IV). a Post-therapy radioactive iodine (5.55 GBq of I-131) whole-body scan showed three unexpected foci of tracer uptake in the left shoulder and abdomen. b–d SPECT/CT images clearly demonstrated bone metastasis of the left scapula and two metastatic nodules in the omentum and retroperitoneum. e–g Retrospective review of preoperative F-18 FDG PET/CT showed two small high-attenuating nodules without significant FDG uptake in the corresponding abdominal areas (arrows), but no abnormal FDG uptake in the left scapula. Laparoscopic excision for the omental and retroperitoneal mass was done 1 month later, and metastatic thyroid cancer with cystic change was confirmed at pathologic findings. Her stimulated serum thyroglobulin gradually decreased from 270.2 ng/ml at the pre-ablation period to 26.1 ng/ml. Post-therapy SPECT/CT findings did not change the TNM staging, but contributed to changes in patient management by detection of unexpected metastatic lesions