False-Positive Radioiodine Uptake From an Intracranial Surgical Clip

Abstract

A 73-year-old man with papillary thyroid cancer underwent total thyroidectomy and bilateral neck dissections. He was subsequently treated with 131 I. The posttherapy scan showed radioiodine uptake at the left supraorbital region, which localized to a metallic surgical clip. There was no evidence of metastasis in this area. This is not a commonly reported finding. Knowledge of this false-positive finding can help avoid unnecessary workup and treatment.

False-positive radioiodine uptake after radioiodine treatment in differentiated thyroid cancer

“…Overall, the literature showed 145 case reports and two series regarding false-positive 131 uptake after RIT For the reasons stated above, we excluded 129 papers, considering only those in which SPECT/CT was performed. A total of 18 papers were thus included: 1 series [17] and 17 case reports [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34]. The series reported 23 cases of falsepositive results: 15 in the chest, six in the pelvis, one in the cranium, and one in the abdomen.…”

“…A total of 15 cases regarded uptake in the abdomen/pelvis: six in the kidney (cysts), five in the ovary (teratoma, benign cysts and malignant disease), two in the uterus and the others in not well-characterized sites [22][23][24][25][26][27][28][29]. Three cases reported uptake in the head: two surgical clips, and one on one eye [30,31,33]. A few other cases were in other sites [24,32].…”