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

Abstract

A 65-year-old male who had previously received curative treatment for a pineal tumor presented with an extremely rare case of primary central nervous system (CNS) primitive neuroectodermal tumor (PNET) of the spinal cord manifesting as progressive tetraparesis. Although the histology was not verified, highly radiosensitive tumor was suspected because of the benign clinical course for over 20 years after only radiation therapy. Magnetic resonance imaging demonstrated an intramedullary tumor extending from C5 to T1. He underwent partial resection and histological examination revealed blue tumor with undifferentiated small round cells. Immunohistochemically, c-kit was negative but CD99 was strongly and diffusely positive. Therefore, rearrangement of the Ewing sarcoma gene was examined to determine the presence of peripheral type of PNET. The results were negative and systemic workup revealed no other disease. These findings led to the diagnosis of primary intramedullary CNS PNET of the spinal cord, and suggested that the spinal cord tumor occurred independently of the prior pineal disease. The residual tumor was controlled by postoperative local radiation therapy.

Cervicomedullary primitive neuroectodermal tumor of the spine: Case report

“…Primary spinal cord tumors (PSCT) comprise 2%–4% of all primary nervous system tumors and are ~15 times less frequent than comparable primary intracranial tumors. [49] Based on their anatomical compartment, PSCTs are divided into three main categories: extradural, intradural extramedullary, and intradural intramedullary tumors. Extradural tumors mainly consist of secondary metastases; in contrast, intradural extramedullary tumors mainly consist of meningiomas (50%) and peripheral nerve sheath tumors (50%).…”

“…[15] Less frequent types of primary tumors such as primitive neuroectodermal tumors (PNETs) have an even lower overall incidence in adults, which is estimated at ~0.62 per million in the US population[20] and are even less frequently located in the spinal cord proper, with ~107 such cases described in the literature. [913]…”

Cervicomedullary intramedullary peripheral primitive neuroectodermal tumor with intratumoral bleed: Report of one case and review of literature

“…PNET rarely affect the spine and may involve extradural, intradural extramedullary, as well as intramedullary compartments. [ 2 ] PNETs arise de novo in the spine or be secondary to drop metastasis. Hence, screening MRI of the entire craniospinal axis needs to be performed.…”

“…Management strategies employed by different authors have largely been extrapolated from studies on medulloblastomas. [ 2 10 ] Because these tumors are poorly demarcated from the normal cord substance, decompression under constant monitoring using somatosensory evoked potentials/motor evoked potentials (SSEP/MEP) is recommended. Adjuvant therapy with a combination of radiochemotherapy has met with moderate success.…”

“…PNET involving the spine is an even rarer occurrence. [ 2 ] Spinal PNETs can be either primary or may develop secondary to subarachnoid dissemination of intracranial PNET. These can be extradural, intradural, or rarely, purely intramedullary in location.…”