Résumé
A 79-year-old man anteriorly treated for primary central nervous system diffuse large B-cell lymphoma with MRI complete response after immunochemotherapy was referred 1 year later for 18FDG PET/CT because of right persistent lombosciatic radicular pain for 6 months with negative medullary and spine MRI and negative cerebrospinal fluid cytology. Linearly intense uptake was observed in several roots of lumbosacral plexus, highly suggestive of peripheral neurolymphomatosis relapse. No specific treatment was engaged because of rapid decrease of performance status leading to death.