First Spinal Axis Segment Irradiation with Spot-scanning Proton Beam Delivered in the Treatment of a Lumbar Primitive Neuroectodermal TumourCase Report and Review of the Literature

Primary primitive neuroectodermal tumor of the lumbar extradural space

“…22 Most cases of PNET involving the spinal cord are drop metastases from primary intracranial tumors. 2,6,17,26,32,33 A primary intraspinal PNET is rare, and only 41 cases have been reported in the English-language literature. These tumors may originate in the extra-or intradural spaces, with a predilection for the cauda equina.…”

“…These tumors may originate in the extra-or intradural spaces, with a predilection for the cauda equina. [6][7][8]19,23,26,31,32 This might be due to the fact that the cauda equina is the portion of the peripheral nervous system in which the axons have become dependent on Schwann cells for the maintenance of their myelin sheaths. Before the diagnosis of a primary spinal PNET can be confirmed, the more common drop metastases of intracranial origin must be excluded.…”

“…The 10 cases reported in the literature are summarized in Table 1. 1,3,8,11,13,19,20,25,31,32 The intramedullary tumor may have originated from the spinal cord, and the primary spinal extradural tumor may have arisen from vertebrae, soft tissue, or spinal nerve roots, which belonged to peripheral PNET. 13 These tumors tend to occur in young adults and children.…”

“…Extradural localization of spinal PNET is more frequent in children and young adults, whereas intradural-extramedullary or intramedullary localizations are more common in adults. 6,7,19,23,31,33 The tumor involved the lumbar spine 8,13,32 and the thoracic spine 1,3,31 in 3 patients each, and the cervical spine, the cervicothoracic spine, 11 the lumbosacral spine, 20 and the sacral spine 25 in 1 patient each. Similar to our patient, only 1 patient in the literature had a spinal PNET arising from the extradural space in the lumbar region with dural sac compression and extension into the paravertebral muscles.…”

“…Similar to our patient, only 1 patient in the literature had a spinal PNET arising from the extradural space in the lumbar region with dural sac compression and extension into the paravertebral muscles. 32 Also, there were 2 patients who had an extradural and paravertebral dumbbell tumor at the cervicothoracic (C6-T3) 11 and cervical (C2-4) spine. 19 The duration of symptoms was variable (range 9 days-4 months).…”