[Peripheral neurofibromatosis and involvement of lumbosacral nerves. Value of imaging]

We report a case of giant plexiform neurofibromatosis revealed by a sensori-motor, axo-myelinic polyneuropathy. Only the lumbar and sacral spinal nerves were involved in this peripheral form of Von Recklinghausen's disease. The polyneuropathy was due to compression of the nervous fibers by the neurofibromatous tumors. Ultrasonography DTPA 99 m Technetium scintigraphy, CT and MRI were the diagnostic procedures. MRI proved superior to CT in demonstrating the extent of the lesions. Biopsy confirmed the diagnosis. This form of neurofibromatosis did not involve the central nervous system, cranial nerves of cervicothoracic spinal nerves and roots; nor was there any visceral involvement, particularly endocrine neoplasia.