False-positive 131I whole-body scan in well-differentiated thyroid cancer patient with respiratory bronchiolitis.

(131)I whole-body scan is performed during treatment and follow-up after radioiodine treatment to detect functioning thyroid remnant and metastatic lesions in differentiated thyroid carcinoma (DTC). False-positive scans are rare, but may cause a potential pitfall by misleading to unnecessary radiation exposure from inappropriate radioiodine treatment. We report a case of papillary thyroid cancer patient with false-positive (131)I scan in the lung due to pulmonary bronchiolitis. Clinical correlation and imaging characteristics obtained from additional SPECT/CT images are very helpful to indicate this lesion as a benign condition.