Primary disseminated central neurocytoma: cytological and MRI evidence of tumor spread prior to surgery

Abstract

Since its description in 1982, central neurocytoma (CN) has been a relatively innocuous rare tumor of the central nervous system. Comprising of less than 0.5% of all intracranial tumors, most are reported to be slow growing, with low recurrence rates, and a favorable prognosis. Because of its rarity, its cellular biology, prognosis, and treatment strategies are difficult to ascertain. Its low-grade nature allows for continued growth before signs and symptoms of increase intracranial pressures ensue. Some authors theorize CN may derive from bipotential precursor cells of the periventricular germinal matrix, which are capable of both neuronal and glial differentiation, but maintain a low proliferative potential after birth. Several retrospective studies indicate that a MIB-1 index of greater than 2-3% will show a recurrence rate of 48-63%, respectively. Of hundreds of cases reported, the incidence of recurrence is very low, which makes aggressive forms of this tumor difficult to study. There are only 12 cases of craniospinal dissemination reported since its inception. The diagnoses of dissemination in these cases are made only after surgical intervention. We report the only case of primary disseminated CN, diagnosed on radiographic studies, and confirmed by cytology of the cerebral spinal fluid, prior to any kind of intervention. These cases may represent a subgroup of a more aggressive CN, which requires more assertive surveillance including CSF sampling and routine imaging of the neuroaxis.

Diffuse central neurocytoma with craniospinal dissemination

“…Though the majority of CN exist in a localized form, 12 patients with craniospinal dissemination following surgical resection have been reported, 8-10,5,11-14 and a recent study documents a single case of craniospinal spread prior to any procedural intervention. 3 Furthermore, multifocal disease is rare, as the majority of lesions reside solely within the ventricular system. The present report represents a rare case in the pediatric population of a diffuse CN with craniospinal dissemination identified at the time of initial diagnosis with immunohistochemical evidence of an elevated Ki-67 proliferation index.…”

“…1 First described by Hassoun et al in 1982, 2 CN represent 0.25 to 0.5% of all intracranial tumors in adults, and comprise an even smaller proportion of pediatric CNS tumors. 3 Purported to arise from bipotential precursor cells of the periventricular germinal matrix, these mixed neuroglial tumors classically occur in the subependymal layer of the lateral ventricle near the foramen of Monro and appear as sharply demarcated, solitary, intraventricular lesions. 4 Multifocal disease is exceedingly rare.…”

“…[1][2][3][4] Advances in endovascular techniques have allowed treatment of many aneurysms previously considered extremely high risk or inoperable, however, substantial risk remains for aneurysms of the vertebrobasilar (VB) system. [1][2][3][4][5][6][7][8][9] A conservative approach may be reasonable in asymptomatic elderly patients; however, mass effect on the brainstem and risk of thromboembolisis and rupture often demand intervention. With progressively enlarging symptomatic aneurysms, relative risks and benefits of limited treatment options must be carefully weighed.…”

Dural Metastasis of Atypical Extraventricular Neurocytoma with the Codeletion of Chromosomes 1p/19q

“…2 In addition, two cases of disseminated neurocytoma designated as extraventricular central neurocytoma have been reported, 13 but these would have been more appropriately diagnosed as CNC, because MRI revealed no evidence of dissemination. 14 No predictive indicator of dissemination has been described, but an uncommonly high MIB-1 LI, atypical histological features and advanced age are associated with an increased likelihood of recurrence. 3 The MIB-1 LI is related to proliferative potential and is believed by some to be the best indicator of poor outcome.…”

Infiltrative brainstem and cerebellar neurocytoma

“…Rarely, such tumors have been described in extraventricular sites. 1,[5][6][7][8][9]12,13,[15][16][17][18]20,22,25 We report the case of a low-grade neurocytoma arising primarily in the brainstem and involving the cerebel-lum, with spread along the CSF pathways to the lateral and third ventricles. A neurocytoma presenting with disease in all of these locations simultaneously has not been previously reported.…”