Staging of metastatic melanoma by whole-body positron emission tomography using 2-fluorine-18-fluoro-2-deoxy-D-glucose

Metastatic melanoma was staged in 15 patients using whole-body positron emission tomography (PET) and the radiopharmaceutical 2-fluorine-18-fluoro-2-deoxy-D-glucose (FDG). PET correctly demonstrated 30 metastases in lung, brain, pancreas, nasal cavity, skin and subcutaneous tissue, and lymph nodes. It detected 97% of all metastases exceeding its spatial resolution (> 5 mm). Two cutaneous metastases (approximately 3 mm) did not show increased FDG uptake; the overall detection sensitivity was 91%. Two false-positive lesions in one patient were due to severe wound infection. PET correctly excluded malignancy in four cases where suspicious lesions were found with conventional cross-sectional imaging modalities but later ruled out by fine-needle biopsy. PET therefore proved to be an excellent method for staging of metastatic melanoma. Due to its high sensitivity for malignant lesions and the possibility of covering the whole body in one examination, it can replace staging techniques employing multiple imaging modalities: chest X-ray, ultrasonography and computed tomography. Furthermore, it provides information on the malignant potential of the detected lesion.