Benign Hepatic Cyst Mimicking a Functional Thyroid Carcinoma Metastasis on Whole-Body I-131 Imaging

Abstract

A 56-year-old woman received an ablative dose of 1-131 after total thyroidectomy for a 15-mm follicular carcinoma. Gamma camera imaging performed 10 days later revealed a focus of liver uptake suggestive of a solitary, functional metastasis. Subsequent computed tomographic (CT) images showed a benign hepatic cyst at the site of uptake. Cysts in other organs such as breast and kidney have been reported as causes of false-positive I-131 scans, but this is the first reported case of uptake by a benign hepatic cyst.