Central nervous system myelomatosis is uncommon and is associated with a particularly poor prognosis. PET images, from a 53-year-old man referred to a fully digital F-FDG PET for relapsed multiple myeloma, revealed high F-FDG uptakes located in the cortex and sulci of the right central area and within the meningeal envelopes of the cerebellum, the trigeminal nerves, and on the spinal canal. These particular uptakes gave evidence of a central nervous system myelomatosis subsequently confirmed by plasma cells documented in cerebrospinal fluid. Such interesting images could be obtained owing to the potential of high-resolution images provided by fully digital F-FDG PET.