Case Report: Synchronous primary lung and thyroid cancers - management informed by multimodal imaging and pathologic...

Management of recurrent thyroid cancer with concurrent pulmonary lesions remains challenging because of tumor heterogeneity. Here, we demonstrate that dual-modality imaging-comprising ¹⁸F-fluorodeoxyglucose (FDG) PET/CT and ¹³¹I-NaI SPECT/CT is essential for characterizing the metabolic and functional landscape of metastatic disease. Our analysis revealed a significant phenotypic discordance, which includes consistent GLUT1/HK2-driven hypermetabolism contrasted with heterogeneous NIS expression across metastatic lesions. This variability in NIS levels was the primary determinant of divergent RAI uptake and subsequent therapeutic efficacy. These results validate a multimodal approach involving aggressive cytoreductive surgery and high-dose RAI and underscore the importance of identifying molecular drivers of resistance to optimize outcomes in patients with advanced RAI-refractory thyroid cancer.