Pitfalls of I-131 whole body scan interpretation: bronchogenic cyst and mucinous cystadenoma.

Whole body iodine scans are routinely performed in the nuclear medicine department as part of the management of differentiated thyroid carcinoma. Similarly, radioactive iodine has a well-established role as an adjunct to thyroidectomy in the treatment of these patients. A thorough understanding of the normal, benign, and pathologic biodistribution of iodine is imperative for the nuclear medicine physician. This knowledge leads to the accurate determination of the presence of metastatic or recurrent carcinoma, and may even facilitate the accurate detection of an undiagnosed condition. Above all, correct image interpretation avoids unnecessary therapeutic doses. The authors describe 2 unusual examples of false positive findings in fluid-filled cavities that showcase the variety of nonmalignant entities one may encounter when interpreting metastatic surveys.