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| LETTER TO EDITOR |
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| Year : 2011 | Volume
: 59
| Issue : 6 | Page : 926-927 |
Distant extraventricular recurrence in central neurocytoma
BV Savitr Sastri1, A Arivazhagan1, V Santosh2, BA Chandramouli1
1 Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, India 2 Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bangalore, India
| Date of Submission | 25-Aug-2011 |
| Date of Decision | 26-Aug-2011 |
| Date of Acceptance | 10-Oct-2011 |
| Date of Web Publication | 2-Jan-2012 |
Correspondence Address: A Arivazhagan Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore India

DOI: 10.4103/0028-3886.91390
How to cite this article: Savitr Sastri B V, Arivazhagan A, Santosh V, Chandramouli B A. Distant extraventricular recurrence in central neurocytoma. Neurol India 2011;59:926-7 |
Sir,
Central neurocytomas are rare tumors of the central nervous system described first by Hassoun in 1982. [1] We present a rare distant extraventricular recurrence in a patient with an intraventricular neurocytoma.
A 50-year-old male presented with features of raised intracranial pressure and cognitive decline of four months' duration. Examination revealed impaired attention span and papilledema. Contrast computed tomography (CECT) scan of brain [Figure 1]a and b revealed a large intraventricular uniformly enhancing mass predominantly in the right lateral ventricle with a septal attachment. There was significant dilatation of both lateral ventricles. The patient underwent ventriculoperitoneal shunt followed by a right frontoparietal parasagittal craniotomy, interhemispheric transcallosal approach and total excision of the tumor. Histopathological examination of the tumor revealed typical pattern of a central neurocytoma, with a bland histology with sheets of neurocytoma cells and no evidence of hypercellularity or mitosis. Ki-67 labeling index (LI) of the tumor was 0.2% [Figure 2]a and b. He had mild left hemiparesis postoperatively which gradually improved over the next six months. Cranial CECT scan two months following surgery revealed no residual tumor [Figure 1]c and the patient was asymptomatic and followed up. Five years after the first surgery, he developed recurrent generalized tonic clonic seizures and progressively worsening weakness of the left lower limb. Magnetic resonance imaging (MRI) of brain revealed two fresh lesions, a small local recurrence within the right lateral ventricle and another distant extraventricular lesion in the right parasagittal interhemispheric region in proximity to the falx [Figure 1]d. He underwent re-exploration and excision of the parasagittal lesion. The tumor was reddish, vascular with attachment to the falx and evidence of pial invasion. The intraventricular lesion was deemed small and was not resected. Histopathological examination of the lesion revealed neurocytoma, which had foci of hypercellularity, abundant mitosis and a Ki-67 LI of 8% [Figure 2]c, d and e. Cerebrospinal fluid (CSF) examination did not reveal malignant cells. Patient was referred for adjuvant radiotherapy following the second surgery, but has been lost to follow-up since.  | Figure 1: (a and b) Contrast enhanced CT(CECT) brain showing a large enhancing lesion occupying only the lateral ventricle, attached to the septum pellucidum, causing ventriculomegaly. (c) Postoperative CECT brain showing no residual enhancing lesion. The ventricles are collapsed with the shunt in situ. (d) MRI brain post-contrast coronal and sagittal images at five-year follow-up show a large extraventricular recurrence in the right parasagittal interhemispheric region attached to the falx causing mass effect. A small recurrence in the right lateral ventricle is also noted
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 | Figure 2: (a and b) Microphotographs of the initially resected tumor, showing neurocytoma with bland histological features (a; HE stain-original magnification, ˜ 160) and an occasional tumor cell nucleus labeled by MIB-1(b; original magnification, ˜ 160), (c, d and e) On recurrence, the tumor is highly cellular with hyperchromatic nuclei (c; HE stain; original magnification ˜ 320), areas of necrosis (d;HE stain; original magnification, ˜ 80) and higher MIB_1 labeling (e; original magnification, ˜ 160)
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Central neurocytomas, though considered benign, are noted to recur in the ventricles on long-term follow-up even after total resection. [2] Interestingly, very few cases of neurocytoma recurring along the CSF pathway in the ventricles studding the ventricular walls or presenting as small enhancing nodules in the spinal cord have been reported. [3],[4] Takao et al.. in 2003, in a review of seven cases of craniospinal dissemination of neurocytoma did not report any recurrence in the extraventricular location. [4] Parenchymal recurrence was reported in only one study in the literature, in a patient who also had a previous leptomeningeal and bulbar recurrence, though the exact site of parenchymal recurrence in this study was not mentioned. [5]
Subarachnoid spread within the intracranial cavity resulting in a symptomatic dural-based focal mass has not been reported in the literature to the best of our knowledge. The recurrence in the present case can be possibly attributed to tumor cell implantation along the surgical corridor considering that the initial tumor was excised by the interhemispheric transcallosal approach. We propose that adequate care needs to be taken to irrigate the trajectory well and remove tumor fragments before closure to prevent such a rare recurrence along the trajectory. This form of recurrence has been previously described rarely in some benign tumors such as meningiomas and craniopharyngiomas. [6],[7] Interestingly, the tumor demonstrated an escalation in the Ki-67 LI from zero in the first specimen to 8% in the recurrent tumor. A similar fourfold increase in the proliferative index has been reported previously in the literature, which underlines the need for long-term follow-up of these tumors. [8] The present case highlights a rare possibility of extraventricular recurrence along the operative trajectory in neurocytoma, not reported previously.
| » References | |  |
| 1. | Hassoun J, Gambarelli D, Grisoli F, Pellet W, Salamon G, Pellissier JF, et al. Central neurocytoma. An electron-microscopic study of two cases. Acta Neuropathol 1982;56:151-6.  [PUBMED] |
| 2. | Sharma MC, Deb P, Sharma S, Sarkar C. Neurocytoma: A comprehensive review. Neurosurg Rev 2006;29:270-85; discussion 85.  [PUBMED] [FULLTEXT] |
| 3. | Eng DY, DeMonte F, Ginsberg L, Fuller GN, Jaeckle K. Craniospinal dissemination of central neurocytoma. Report of two cases. J Neurosurg 1997;86:547-52.  [PUBMED] [FULLTEXT] |
| 4. | Takao H, Nakagawa K, Ohtomo K. Central neurocytoma with craniospinal dissemination. J Neurooncol 2003;61:255-9.  [PUBMED] [FULLTEXT] |
| 5. | Favereaux A, Vital A, Loiseau H, Dousset V, Caille J, Petry K. Histopathological variants of central neurocytoma: Report of 10 cases. Ann Pathol 2000;20:558-63.  [PUBMED] [FULLTEXT] |
| 6. | Liu JM, Garonzik IM, Eberhart CG, Sampath P, Brem H. Ectopic recurrence of craniopharyngioma after an interhemispheric transcallosal approach: Case report. Neurosurgery 2002;50:639-44; discussion 44-5.  [PUBMED] [FULLTEXT] |
| 7. | Mahore A, Chagla A, Goel A. Seeding metastases of a benign intraventricular meningioma along the surgical track. J Clin Neurosci 2010;17:253-5.  [PUBMED] [FULLTEXT] |
| 8. | Christov C, Adle-Biassette H, Le Guerinel C. Recurrent central neurocytoma with marked increase in MIB-1 labelling index. Br J Neurosurg 1999;13:496-9.  [PUBMED] |
[Figure 1], [Figure 2]
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