Neurocytoma: a comprehensive review

Abstract

Central neurocytomas (CN) are uncommon tumors of the central nervous system, most descriptions of which available in the literature are in the form of isolated case reports and small series. Owing to this rare incidence, diagnosis and management of this neoplasm remain controversial. Usually, these tumors affect lateral ventricles of young adults and display characteristic neuroimaging and histomorphologic findings. Neurocytomas often mimic oligodendrogliomas when confirmation of diagnosis rests on immunohistochemistry, ultrastructure, and genetic studies. Extraventricular neurocytomas, situated entirely within the brain parenchyma and spinal cord, have also been reported. Typically, CN are associated with a favorable outcome although cases with more aggressive clinical course with recurrences are not unknown. MIB-1 labeling index (LI) of >2% often heralds poor prognosis and tumour recurrence. Safe maximal resection is presently considered the ideal therapeutic option, with best long-term prognosis in terms of local control and survival. The role of adjuvant radiotherapy apparently seems to benefit patients with incomplete resection and in atypical neurocytoma. Utility of other therapeutic regimen, however, remains shrouded in controversy. Epidemiology, histogenesis, clinical profile, histology, neuroimaging and therapeutic modalities of neurocytomas have been comprehensively reviewed, with special emphasis on CN and extraventricular neurocytomas and their atypical counterparts.

Central neurocytoma: A clinical, radiological and pathological study of nine cases

“…Most of these symptoms are attributed to increased intracranial pressure secondary to obstructive hydrocephalus. Most authors report that central neurocytomas affect young adults without predilection for either sex [43]. However, in our series there were two patients with age over 40 years and female patients predominated.…”

“…Central neurocytoma first was described in 1982 by Hassoun et al as a midline neuronal tumor characterized by its intraventricular location, greater frequency among young adults, specific radiologic features, and good postoperative prognosis due to its benign clinical course [1,2,4,6,9,36,39,43]. Neurocytoma can arise from the septum pellucidum, fornix, or the walls of the lateral ventricles (subependymal layer).…”

“…Neurocytoma can arise from the septum pellucidum, fornix, or the walls of the lateral ventricles (subependymal layer). It 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 [4,42,43,44]. Central neurocytoma has a long clinical course.…”

“…Limited data reported previously showed that central neurocytomas have low proliferative potential [3,43,44]. However, anaplasia has been demonstrated in recent literatures.…”

“…The histopathologic appearance of a central neurocytoma can be similar to that of an oligodendroglioma. Both neoplasms have small uniform cells with rounded nuclei and scant cytoplasm resembling perinuclear halos ('fried egg' appearance), and many of the intraventricular tumors diagnosed as oligodendrogliomas may indeed represent central neurocytomas [18,36,39,43]. However, alternating fibrillary and cellular areas, scant mitotic activity and a tendency to form ill-defined rosettes in the latter are features against oligodendroglioma [19].…”