False Positive Result in the Whole-Body Scan with 131-I in the Follow-up of Differentiated Thyroid Cancer: The Fistula Tract Accompanied by the Suture Granuloma
Abstract
The role of radioiodine-131(I-131) Whole- body scan (WBS) is crucial regarding the management of patients with differentiated thyroid carcinoma (DTC) in detecting normal thyroid remnants and recurrent or metastatic disease. Although I-131 is a sensitive marker for detection of thyroid cancer, radioiodine uptake is not specific for thyroid tissue. According to several reports, various tissues or non-thyroidal pathologic processes were associated with false-positive WBS with radioiodine. In this case report we reported that the false positive result was present due to the fistula accompanied by the suture granuloma. A 47 year-old woman underwent total thyroidectomy for papillary thyroid carcinoma.A false-positive iodine uptake in the midline neck was determined by a diagnostic I-131 whole body scan. I-131 whole body scan was correlated with ultrasonography (US) and computed tomography (CT) imaging features, biochemical data, clinical history, and physical examination. The lesion was demonstrated to be a fistula tract accompanied by the suture granuloma. The false- positive findings in the I-131 whole-body scan should be confirmed with other imaging modalities, available biochemical data, clinical history, and physical examination in order to avoid unnecessary treatments.
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