|Year : 2017 | Volume
| Issue : 2 | Page : 125-127
Neuroradiological and histopathological findings of intraventricular central neurocytoma
Department of Radiology, St. John's Medical College, Bengaluru, Karnataka, India
|Date of Web Publication||14-Mar-2017|
Dr. Reddy Ravikanth
St. John's Medical College, Bengaluru - 560 034, Karnataka
Source of Support: None, Conflict of Interest: None
Central neurocytomas are rare neuroectodermal tumors believed to arise from the subependymal matrix of the lateral ventricles. Intraventricular central neurocytoma is a benign primary central nervous system tumor of neuronal origin that is usually located within the lateral and third ventricles. Central neurocytoma should be considered in the differential diagnosis of lesions involving bilateral lateral ventricles with symmetrical growth around the center of septum pellucidum in young patients. Here, we report the radiological and histopathological findings in a rare case of intraventricular central neurocytoma.
Keywords: Brain neoplasms, central neurocytoma, fractionated radiotherapy, immunohistochemistry, magnetic resonance imaging, synaptophysin
|How to cite this article:|
Ravikanth R. Neuroradiological and histopathological findings of intraventricular central neurocytoma. CHRISMED J Health Res 2017;4:125-7
|How to cite this URL:|
Ravikanth R. Neuroradiological and histopathological findings of intraventricular central neurocytoma. CHRISMED J Health Res [serial online] 2017 [cited 2018 Jan 17];4:125-7. Available from: http://www.cjhr.org/text.asp?2017/4/2/125/201990
| Introduction|| |
Central neurocytoma was first described in 1982 by Hassoun et al. as a rare tumor composed by mature neuronal cells which accounts for about 0.5% of primary brain tumors. They are usually slow growing and are considered low-grade malignant tumors and are classified as the WHO Grade II. Typically, all central neurocytomas originate from the lateral ventricles or septum pellucidum and extend intraventricularly. The radiological and pathologic features can be similar to other intraventricular tumors, especially oligodendroglioma. Necrotic and cystic changes are commonly found within the tumor. The presence or absence of contrast enhancement in the solid portions of the tumor, ventricular dilatation, hemorrhage, cystic changes, and vascular signal voids is commonly noted on magnetic resonance imaging (MRI). Immunohistochemistry reveals neuronal marker proteins such as synaptophysin. Here, we report the neuroradiological and histopathological findings in a 27-year-old patient with intraventricular central neurocytoma.
| Case Report|| |
A 27-year-old woman was presented to the emergency department with complaints of chronic and persistent headache for 1 year, worsened in the last 4 months. The headaches lasted for several hours and mostly occurred in the morning which were treated as migraine attacks. On clinical examination, there was mild papilledema; her vital signs were unremarkable, and she had no other focal neurological deficits. The laboratorial tests were normal. The patient was submitted to MRI scan of the brain which revealed an ill-defined irregular hyperintense to the brain on diffusion-weighted imaging [Figure 1]a, T1 hypointense, T2/T2 fluid-attenuated inversion recovery heterointense lesion measuring 8.0 cm × 7.0 cm × 5.5 cm (AP × ML × CC) involving bilateral lateral ventricles with extension into the third ventricle causing obstructive hydrocephalus [Figure 1]b. The fourth ventricle was not dilated. The lesion caused displacement of the choroid plexus laterally with splaying of the internal cerebral veins and associated corpus callosal edema. Inferiorly, the lesion extended into the posterior fossa with mass effect on the cerebellar hemispheres and midbrain [Figure 1]c. On postcontrast imaging, there was moderate inhomogeneous enhancement of the mass lesion. Imaging characteristics and location of the lesion were highly suggestive of intraventricular central neurocytoma. Surgery was performed, and tumor was completely resected. Macroscopically, the tumor masses were irregular and friable with hemorrhagic areas. Microscopically, the tumor was composed of uniform round cells with clear cytoplasm, interlaced vascular pattern and nucleus-free areas [Figure 2]a. Immunohistochemistry revealed positive expression of synaptophysin [Figure 2]b. Histopathological diagnosis of tumor was central neurocytoma. She was submitted to radiation therapy, using a single phase localized three-dimensional irradiation in the tumor area in a dose of 54 Gy, divided in 30 fractions of 180 cGy. The patient showed good evolution, with no recurrence in the control computed tomography (CT) scans.
|Figure 1: (a) An ill-defined irregular lesion involving bilateral lateral ventricles and septum pellucidum appearing hyperintense to the brain on axial diffusion-weighted magnetic resonance imaging diffusion-weighted imaging. (b) Axial T2 fluid-attenuated inversion recovery magnetic resonance image showing a heterointense lesion involving bilateral lateral ventricles with extension into the third ventricle causing obstructive hydrocephalus. (c) Coronal T2-weighted magnetic resonance image showing the lesion extending into the posterior fossa with mass effect on the cerebellar hemispheres and mid-brain|
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|Figure 2: (a) Lesion was composed of uniform round cells with clear cytoplasm, interlaced vascular pattern, and nucleus-free areas (H and E, ×200). (b) Positive expression of synaptophysin in the lesion (SP, ×200)|
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| Discussion|| |
Central neurocytomas were first defined by Hassoun et al. in 1982. They described two cases of primary calcified intraventricular tumors with features of neuronal differentiation. The term central neurocytoma is reserved for neurocytomas that occur in the ventricular system. Neurocytoma can arise from the septum pellucidum, fornix, or the walls of the lateral ventricles (subependymal layer). Central neurocytomas typically occur in the lateral ventricle with or without extension into the third ventricle. Approximately 50% of central neurocytomas are located in the anterior portion of a lateral ventricle around foramen of Monro, 15% in both lateral and third ventricles and 15% are bilateral.
On MRI, central neurocytoma appears as a heterogeneous well-circumscribed, lobulated mass isointense or slightly hypointense to gray matter on T1-weighted images and hyperintense on T2-weighted images. Punctate or coarse calcifications and multiple small cysts within the tumor are often observed. Mild-to-moderate contrast enhancement is common. Hydrocephalus, increased T2 signal intensity in the adjacent periventricular white matter, prominent flow voids, and intratumoral hemorrhage may also be seen. Proton MR spectroscopy of the central nervous system shows elevated choline, decreased creatine, and N-acetylaspartate. Intraventricular oligodendroglioma or ependymoma may be indistinguishable from central neurocytoma without immunohistochemical studies. CT reveals these tumors to be hyperattenuating to white matter with calcifications in majority of the cases.
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. Immunohistochemical studies showed positivity for neuron-specific enolase (NSE) and synaptophysin, an evidence of neuronal differentiation. This immunocytochemical marker – NSE is found in early stages of neurogenesis and synaptophysin – is present only in mature neoplastic ganglion cells, demonstrating neuronal origin of the tumor.
The most important treatment of central neurocytoma is surgery. The main aims of surgery are to establish the cerebrospinal fluid pathway, determine the histological diagnosis, and accomplish maximal surgical resection with minimum risk of neurological impairment. Total resection of the tumor provides the best outcome. A transcortical-transventricular and transcallosal-transventricular routes are the most common surgical approaches for unilaterally located tumors in the anterior part of lateral ventricles. An interhemispheric transcallosal-transventricular approach may be necessary for the bilateral tumors or in the cases which extend to the third ventricle. Fractionated radiotherapy should be considered for residual tumors with anaplastic features.
| Conclusion|| |
When a mass is centered on the choroid plexus, a highly vascular tumor either choroid plexus papilloma, choroid plexus carcinoma, meningioma, or metastasis should be suspected. However, the heavy lobulated appearance of the central neurocytoma favors the diagnosis rather than possibilities. Central neurocytoma should be considered in the differential diagnosis in tumors in young patients involving bilateral lateral ventricles and septum pellucidum, causing hydrocephalus, showing moderate contrast enhancement and histopathological features such as tumor proliferation, vascular proliferation, and synaptophysin expression.
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Conflicts of interest
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[Figure 1], [Figure 2]