Hyperprolactinemia-Associated Breast Uptake of Radioiodine Following ^(131)I Postablation Scan in Differentiated Thyroid Cancer

Abstract

Scanning with whole-body ^(131)I scintigraphy after surgery has been a valuable diagnostic modality in the surveillance of patients with differentiated thyroid cancer. Radioiodine uptake is rarely observed in non-lactating breast tissue, which mimics thyroid cancer metastasis. We now report a case of a 45-year-old female thyroid cancer patient who underwent radioiodine therapy, and in whom breast uptake of radioiodine was observed on a post-therapy whole body scan. Her serum prolactin level was elevated to 328 ng/mL at the time of the radioiodine uptake, and the hyperprolactinemia was induced by her antipsychotic medications. Six months after she discontinued that medication, her serum prolactin level was normalized to 12.6 ng/mL and breast uptake of iodine was no longer present in a follow-up whole body scan.