Skull Base Neurocytoma: Case Report and Review of the Literature of Extraventricular Neurocytomas

Abstract

We report a rare skull base neurocytoma. A 44-year-old female with a history of focal seizure and progressive right-sided weakness sought treatment at an outside institution, where she underwent total resection of a "left medial sphenoid wing paraganglioma" in 1984. In 1995 after experiencing intense left-sided headaches for 3 weeks, the patient presented to our institution. Magnetic resonance imaging revealed a large local recurrence. She had deficits dating to her initial surgery, including moderate right-sided hemiparesis, complete left ophthalmoplegia, and left facial numbness.The patient underwent a craniotomy with extensive removal of the involved sphenoid bone and a subtotal resection of the tumor. Neurocytoma was diagnosed based on strong immunohistochemical staining for synaptophysin and no reactivity for glial fibrillary acidic protein. Postoperatively, her headaches resolved completely and her neurologic status remained at baseline. The residual tumor was treated with radiation therapy. After 5 years, she remains clinically and radiographically stable.Although typically located adjacent to the foramen of Monro, neurocytomas have now been reported in almost every subcompartment of the craniospinal axis. Finding neurocytomas in extraventricular locations may require revisiting the current theory that subependymal progenitor cells are the cells of origin for these tumors.

Imaging Findings of Extraventricular Neurocytoma: Report of 3 Cases and Review of the Literature

“…They are more unusual tumors with biologic behavior and histopathologic characteristics similar to the neoplasms that occur in the lateral ventricles. [1][2][3]7 EVNs seemed to exhibit a somewhat larger morphologic spectrum compared with intraventricular neurocytomas. The fourth edition of the WHO classification of tumors of the central nervous system, published in 2007, listed EVN as a new entity.…”

“…10 The MR imaging findings of this entity have been described in previous case reports and in small series. [3][4][5]7,[10][11][12][13][14][15][16][17][18] In many instances, the neurocytoma was well-defined, cystic and heterogeneously solid, and involved the deep white matter or cortical gray matter of the cerebral hemispheres. The solid portion showed varying degrees of enhancement and calcification.…”

Intramedullary neurocytomas in the craniocervical spinal cord: A report of two cases and a literature review

“…Since the first case was reported by Hassoun et al in 1982 ( 3 ), 271 studies regarding ventricular neurocytomas have been published, while only 64 studies regarding extraventricular neurocytoma have been published. By July 2012, extraventricular neurocytoma had been reported in the cerebrum, including the frontal ( 4 ), temporal ( 5 , 6 ), parietal ( 7 ) and occipital ( 7 ) lobes, the pons ( 8 ), the skull base ( 9 , 10 ), the vermis of the cerebellum ( 11 ), the cerebellum ( 12 ), the sellar region ( 13 ), the cauda equina ( 14 ), the thalamus ( 15 ) and the spinal cord ( 16 – 25 ). To date, 17 cases of neurocytoma involving the spinal cord have been reported; nine cases located in the cervical spinal cord ( 16 , 17 , 19 , 21 – 23 , 25 ) and eight cases located in the thoracic spinal cord ( 18 , 20 , 22 , 23 ).…”

Clinicopathological and genetic characteristics of extraventricular neurocytomas

“…As a result, there has been no large‐scale study performing genetic analysis of EVN. Only numerous case reports delineating its clinicopathological features have accumulated 4–6,9–31 . Research into the pathogenesis and genetic abnormalities of EVN have been seriously limited.…”