Focal thoracic uptake mimicking lung metastasis on 131I post-therapy whole-body scan in patients with thyroid carcinoma.

Whole-body 131I scan after total thyroidectomy is important in the evaluation of radioiodine avid metastatic foci in patients with differentiated thyroid carcinoma. False-positive uptakes are occasionally seen in the thoracic region which should be evaluated carefully and not mistaken as lung metastases. We report here 2 cases of abnormal focal thoracic uptake, 1 case of a pleuropericardial cyst and 1 case of focal bronchiectasis, that could potentially be confused with lung metastasis. Careful correlation with diagnostic CT and subsequent follow-up studies suggested that these were not metastatic lesions.