Primary intramedullary primitive neuroectodermal tumor (PNET) – case report and review of the literature

Abstract

Spinal primitive neuroectodermal tumors (PNET) are very rare tumors, and intramedullary localization is even less common. Indeed, amongst the 23 cases of the spinal PNET described in the literature, only eight cases had an intramedullary localization. Following the WHO 2000 classification, PNETs have been considered embryonal tumors composed of undifferentiated neuroepithelial cells with a capacity of differentiation into different cellular lines, such as astrocytic, ependymal, melanotic and muscular. They have been considered to arise from a neoplastic transformation of primitive neuroepithelial cells, thereby making their presence possible in any part of the central nervous system. The optimal treatment for these malignant tumors is not yet clear, although, over the years, radiotherapy has been considered the best treatment for spinal PNETs. The described case is that of a 38-year-old man with a primary intra-extramedullary PNET, treated by laminectomy, open biopsy and chemotherapy. The patient, 18 months after the onset of his symptomatology, died without cerebral tumor involvement.

Intramedullary Primitive Neuroectodermal Tumor Presenting With Rapidly-Progressive Cauda Equina Syndrome -Case Report-

“…Many tumors have been treated with a combination of surgical resection/biopsy, chemotherapy, and Neurol Med Chir (Tokyo) 50, November, 2010 Intramedullary PNET radiotherapy. 1,5,6,12) However, some cases were managed by surgical resection and serial chemotherapy 4,13) or surgery followed by intensive radiation therapy. [7][8][9] Due to the rarity of this condition and the lack of case-controlled studies, the most advantageous therapy to achieve the longest survival times, whether surgical resection, chemotherapy, radiotherapy, or various combinations, has not been determined.…”

“…14) In previous cases, the degree of tumor resection and prognosis were not significantly correlated. 1,[4][5][6][7][8][9]12) Further case accumulation is essential to understand intramedullary PNET. Our patient showed improvement in motor function after subtotal tumor resection, which may be primarily attributable to the tumor location in the conus medullaris that is not directly involved in skeletal motor function.…”

“…1,4,5,13) No chemotherapy was administered because our patient rejected this treatment. Instead, he elected to undergo intensive radiation therapy.…”

“…1,3,8,9,12) Intramedullary PNET is even more rare and has been documented primarily as case presentations and short series. [4][5][6][7]13) Cauda equina syndrome refers to a constellation of symptoms that result from damage to the cauda equina. This syndrome may present as sciatica, low-back pain, saddle analgesia, decreased rectal tone, absent bulbocavernosus, patellar, and Achilles reflexes, bowel and bladder dysfunction, and lower extremity weakness.…”

Central Nervous System Primitive Neuroectodermal Tumor of Spinal Cord Developing 20 Years After Curative Treatment of Pineal Tumor -Case Report-

“…Approximately 20 cases of pPNET have been reported and specific chromosomal translocations have been ascribed to genetic mechanisms. Only 12 cases of CNS PNET have been reported 1,2,4,5,7,11,12,13,15,16,18,19) and the genetic pathway is still unclear. A definite distinction between the two is critical for future molecular targeting therapy.…”