False-Positive Radioactive Iodine Uptake Caused by Cervical Myofascitis in a Patient With Differentiated Thyroid Carcinoma

Abstract

A 31-year-old woman with a history of papillary thyroid cancer underwent ablative 131I therapy. Posttherapeutic whole-body 131I scintigraphy revealed abnormally increased activity in the neck. Additional SPECT/CT images localized the activity in the bilateral peripheral fascia of the platysma.

Radioiodine Uptake at Suture Site Granuloma Mimicking Neck Node Metastasis on 131I Whole-Body Iodine Scintigraphy

“…Any focal area of increased 131 I uptake should be interpreted in the background of clinical history, physical examination, and histopathological features of primary malignancy as well as serum thyroglobulin levels. This case further emphasizes role of SPECT/CT in preventing false interpretation of planar images 5–9 . In the present case, abnormal focal uptake in the thyroid bed was suspected to be false-positive due to disproportionately low thyroglobulin levels and was confirmed to be due to localization of 131 I in suture granulomas on SPECT/CT as well as USG.…”