[18F]-FDG PET-CT in Malignant Melanoma

<b>Background/Objectives</b>: Malignant melanoma (MM) is an aggressive neoplasm with a rising global incidence. Accurate staging and risk stratification are essential for guiding therapeutic decisions and improving patient prognosis. [18F]-FDG PET-CT enables the non-invasive assessment of tumor metabolic activity, offering a valuable adjunct to histopathological evaluation. However, the correlation between PET-CT findings and established prognostic markers in MM, such as Breslow thickness, ulceration, and mitotic rate, remains insufficiently explored. <b>Methods</b>: This retrospective observational study included 61 patients diagnosed with MM, of whom 48 met the inclusion criteria. Quantitative and qualitative variables such as SULmax, Breslow thickness, Ki-67 expression, and mitotic rate were analyzed using descriptive statistics, while correlations between PET-CT findings, SLNB, and histopathological characteristics were assessed using Spearman's correlation test. A <i>p</i>-value < 0.05 was considered statistically significant. <b>Results</b>: Significant associations were identified between ulceration and both overall metastases (<i>p</i> = 0.01) and pulmonary metastases (<i>p</i> = 0.02). Breslow thickness showed a positive correlation with metastatic spread (<i>p</i> = 0.01), reinforcing its role as a key prognostic indicator. Perineural and vascular invasion were significantly associated with intra-abdominal metastases (<i>p</i> < 0.001 and <i>p</i> = 0.0007, respectively). Tumor-infiltrating lymphocytes (TILs) were inversely correlated with intra-abdominal metastases (<i>p</i> = 0.05), while sentinel lymph node positivity correlated with the presence of regional (<i>p</i> = 0.008) and distant (<i>p</i> = 0.02) metastases. Additionally, subcutaneous SULmax values were significantly higher in male patients compared to females (<i>p</i> = 0.04). <b>Conclusions</b>: Integrating PET-CT metabolic parameters with histopathological markers enhances the assessment of MM aggressiveness and metastatic potential. By refining risk stratification, PET-CT may contribute to personalized therapeutic strategies and improved patient management in MM.