Superior mucoepidermoid carcinoma detection with ⁶⁸Ga-FAPI PET/CT reflects FAP-α expression and MAML2 fusion status.

This study evaluated the diagnostic potential of the FAP-targeted tracer ⁶⁸Ga-FAPI PET/CT in mucoepidermoid carcinoma (MEC), demonstrating its superior sensitivity over ¹⁸F-FDG PET/CT in detecting primary tumors (100% vs. 85.7%) and metastatic lesions (33 lymph nodes and 19 distant metastases), with significantly higher SUVmax and TBR values. High-grade MEC exhibited elevated stromal FAP-α expression, strongly correlating with ⁶⁸Ga-FAPI uptake metrics (r = 0.91–0.96, p < 0.01), while MAML2-negative tumors showed amplified FAP activity, suggesting stromal activation-driven aggressive behavior. These findings highlight ⁶⁸Ga-FAPI PET/CT as a transformative imaging biomarker for accurate grading, metastasis detection, and risk stratification in MEC, offering a non-invasive stromal imaging paradigm to enhance clinical decision-making and targeted therapy for this histologically complex malignancy.