Increased uptake on I-131 whole-body scintigraphy in Warthin tumor despite false-negative Tc-99m pertechnetate salivary gland scintigraphy.

Whole-body I-131 scintigraphy is an important component of the postoperative follow-up of patients with well-differentiated thyroid cancer. However, false-positive scans showing abnormal uptake in the absence of residual thyroid tissue or metastases may occur. Unless recognized as false positive, these abnormal sites of uptake may lead to unnecessary administration of therapeutic doses of I-131. The authors report a patient with Warthin tumor whose I-131 whole-body scan demonstrated increased uptake in the parotid gland, despite a negative Tc-99m pertechnetate salivary gland scintigraphy.