This project will target patients with histopathologically diagnosed mucosal melanoma using \[¹⁸F\]FDG PET/CT imaging for retrospective prognostic evaluation.The primary objective is to explore the value of \[¹⁸F\]FDG PET/CT imaging in the prognostic assessment of mucosal melanoma, and to determine the correlations between quantitative \[¹⁸F\]FDG PET parameters and progression-free survival (PFS) as well as overall survival (OS), so as to provide reference evidence for individualized treatment decision-making.