Bronchiectasis simulating pulmonary metastases on iodine-131 scintigraphy in well-differentiated thyroid carcinoma.

Differentiated thyroid cancer is an uncommon disease that carries a good prognosis when treated adequately. Radioiodine treatment is often used as an adjunct to surgery because this has been associated with increased survival, particularly in the presence of iodine-avid soft tissue metastases. Multiple different false-positive scans can occur in the absence of residual thyroid tissue or metastases. Recognition of these potential false-positive iodine-131 (I-131) scans is critical to avoid the unnecessary exposure to further radiation from repeated therapeutic doses of radioactive iodine. We report a case of physiological uptake of radioactive iodine in the bronchiectatic bronchial tree bilaterally, potentially masquerading as pulmonary metastases.