Teaching Case

A 16-year-old male patient presented with headache and blurring of vision since few months. On examination the patient was afebrile. There was raised cerebrospinal fluid (CSF) pressure with normal CSF analysis.

Non-contrast axial computed tomography (NCCT) image shows a well-defined, lobulated hyperdense mass lesion with internal cystic areas involving body and atria of right lateral ventricle (along septum pellucidum), extending into body of left lateral ventricle, 3rd ventricle and cerebral aqueduct measuring ~ 8.4 (AP)x6.4 (TR) x8 (CC) cm. Lateral and 3rd ventricles were moderately dilated. Magnetic resonance (MR) images show a T1, T2 and FLAIR hyperintense, solid-cystic intraventricular mass lesion. It was abutting bilateral medial temporal lobes. Posteroinferiorly, the lesion is seen to cause mass effect on bilateral cerebellar hemispheres and vermis. There were areas of diffusion restriction and neovascularity within the lesion. Mild subfalcine herniation with midline shift to left side by 2 cm was present. Inferior herniation of cerebellar tonsil by 1.4 cm was seen with central canal dilatation of visualised cervical spinal cord. Subarachnoid spaces around bilateral optic nerves appear prominent with tortuous optic nerves.

Intraventricu¬lar neoplasms may present as an incidental finding at imaging or may manifest with symptoms depending on their location, including symptoms of increased intracranial pressure. These lesions may arise from various ventricular structures, including the epen¬dymal lining, subependymal layer or choroid plexus or they may have an undetermined cell of origin. Neoplasms involving the ventricular system include ependymoma, subependymoma, choroid plexus neoplasms, central neurocytoma, subependymal giant cell tumour, meningioma, rosette-forming glioneuro¬nal tumour, and metastases. [1] The location may vary according to the type of tumour. Choroid plexus papillomas occur mainly in children, with predilection for the lateral ventricles while in adults it usually is more frequently found in the fourth ventricle. Ependymomas are most frequent in the posterior fossa in children, and in adults they are generally supratentorial. [2] Central neurocytoma most commonly involves the lateral ventricle from the foramen of Monro. On plain CT, the tumour usually appears as a lobulated, hyperdense, isodense or mixed lesion. It is seen attached to the septum pellucidum and may extend to both lateral ventricles. Calcifications and cysts may be present. [2] On MR imaging, they present as ‘bubbly’ mass in frontal horn or body of lateral ventricle. They are heterogeneous, mostly isointense to gray matter on T1WI and show heterogeneous, hyperintense appearance with numerous cyst-like areas on T2WI. Low signal on T2* GRE, indicates calcification, blood vessels, or haemorrhage. They demonstrate moderate to strong gadolinium enhancement. The main features of central neurocytoma include: i) a lateral ventricular location, ii) occurrence in young adults, iii) characteristic radiological imaging findings, iv) resemblance to oligodendroglioma or ependymoma on light microscopy, v) a neuronal origin seen on electron microscopic and immunohistochemical examination, and vi) a favorable prognosis with benign biological behavior. [3] Currently, immunostaining for synaptophysin can confirm the neuronal nature as was confirmed in this case.[4] Surgical management with a gross-total resection (GTR) is currently the gold standard treatment for central neurocytomas, which is associated with least recurrence. Radiotherapy and radiosurgery can be regarded as adjuvant treatments when GTR cannot be achieved, the patient is inoperable, or the tumour is aggressive. [5] Written informed patient consent for publication has been obtained.