Transformed Giant Congenital Melanocytic Nevus on 18F-FDG PET/CT.

A 50-year-old man experienced cough and bloody sputum for 1 month. CT detected a mass in the right lung. Staging 18F-FDG PET/CT revealed multiple hypermetabolic lesions in the lung, mediastinum, liver, and bones. Further physical examination revealed black patches in the skin covering most parts of the body, which presented at his birth and were growing very slowly, consistent with giant congenital melanocytic nevus. Pathology examination after biopsy of the lung demonstrated metastatic melanoma.