Detection of Non-FDG-Avid Residual Sinonasal Malignant Melanoma in the Skull Base With 11C-Choline PET and Contrast-Enhanced MRI.

Primary sinonasal melanoma is a rare disease. We present a case of melanoma in sinuses without abnormal F-FDG activity anywhere in the scanned portion of the body. In further assessment, C-choline PET/CT revealed high activity in the paranasal sinuses, skull base, and adjacent brain, in agreement with the high signal on contrast-enhanced T1-weighted MRI scan, which suggested the residual tumor.