Unilateral Chronic Parotitis With 68Ga-DOTA-FAPI-04 PET/CT and 18F-FDG PET/CT Imaging in a Case of a Patient With Papillary Thyroid Carcinoma

Abstract

Abstract The 68Ga-FAPI (fibroblast activation protein inhibitor) radiotracer is a novel and versatile tool in nuclear medicine, exhibiting potential for use in various conditions due to its significant upregulation in cancerous and inflammatory conditions, particularly those involving fibrotic and infectious processes. In this report, we present the case of a patient with papillary thyroid carcinoma who underwent total thyroidectomy and iodine therapy. He was referred because of high thyroglobulin despite negative diagnostic radioiodine imaging (TENIS syndrome). The patient underwent 18F-FDG and 68Ga-DOTA-FAPI-46 PET/CT imaging for metastatic workup and treatment planning. FAPI uptake was observed in the right parotid gland (with no FDG uptake), prompting a 99mTcO4 − salivary scintigraphy. Subsequently, a diagnosis of chronic sialadenitis was made.