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Year : 2016  |  Volume : 11  |  Issue : 4  |  Page : 451

Coexistent dysembryoplastic neuroepithelial tumour and pilocytic astrocytoma

1 Department of Pathology, Government Medical College and Sir Sayajirao General Hospital, Vadodara, Gujarat, India
2 Department of Pathology, Pandit Deendayal Upadhyay Government Medical College and Hospital, Rajkot, Gujarat, India
3 Department of Radiodiagnosis, Rajkot Imaging Center, Rajkot, Gujarat, India

Date of Web Publication7-Jul-2016

Correspondence Address:
Dr. Jitendra G Nasit
C/4, Suryadeep Society, Near Nutan School, Behiend Chankyapuri Society, New Sama Road, Vadodara - 390 008, Gujarat
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1793-5482.145352

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Dysembryoplastic neuroepithelial tumour (DNET) is an uncommon mixed glioneuronal tumour. DNET is classified as Grade I neoplasm in revised World Health Organization classification of tumors of the nervous system. DNET is commonly seen in the temporal lobe of children and young adults with features of pharmacoresistant complex partial seizures. Tumors arising in association with DNETs are rare. Only two cases of pilocytic astrocytoma (PA) arising in DNETs are reported. Surgical excision is the only successful management with favourable prognosis. The development of recurrence and malignancy after subtotal or even after complete excision challenges the premise of stability and highlights the importance of close clinical follow up. Here, a case of DNET with area of PA is described which helps in understanding the pathogenesis and biological behavior of DNET.

Keywords: Dysembryoplastic neuroepithelial tumour, malignant transformation, pilocytic astrocytoma, seizure

How to cite this article:
Nasit JG, Shah P, Zalawadia H. Coexistent dysembryoplastic neuroepithelial tumour and pilocytic astrocytoma. Asian J Neurosurg 2016;11:451

How to cite this URL:
Nasit JG, Shah P, Zalawadia H. Coexistent dysembryoplastic neuroepithelial tumour and pilocytic astrocytoma. Asian J Neurosurg [serial online] 2016 [cited 2020 Aug 7];11:451. Available from:

  Introduction Top

Dysembryoplastic neuroepithelial tumour (DNET) is a rare mixed glioneuronal tumour.[1],[2],[3],[4] In 1993, World Health Organization (WHO) classified the DNET as a Grade I tumour.[2],[4] Only two cases of pilocytic astrocytoma (PA) with DNETs are reported.[1],[2] To the best of our knowledge, this is the third reported case of coexistent DNET with PA. DNET have the potential for recurrence and malignant transformation.[1],[2],[5],[6],[7],[8],[9],[10] The identification of DNET by surgical pathologist has therapeutic and prognostic implications because surgical outcome and prognosis is much better and aggressive chemo-radiotherapy can be avoided.[2],[4],[8],[11],[12] Here, we discuss a case of DNET with PA. We conclude that patients with unresected long standing DNET may develop secondary, histologically different neoplasm in DNET itself.

  Case Report Top

A 14-year-old male presented with complain of headache, vomiting and seizures. He had previous history of epilepsy before three years. Seizures were managed with carbamazepine without definitive diagnosis. There had been increased frequency of medically refractory seizures since 12 months. Neurological examination was unremarkable. Routine laboratory investigations were within normal limits. On magnetic resonance (MR) imaging, left temporal lobe revealed multinodular mass. It was hypointense on T1 and hyperintense on T2-weighted images without surrounding vasogenic edema. Post-contrast scans revealed only small focal enhancement. Little mass effect was seen [Figure 1]. Radiological diagnosis of DNET or low grade astrocytoma was made.
Figure 1: Dysembryoplastic neuroepithelial tumour: (a) Axial T1-weighted MR image shows a hypointense mass in left temporal lobe; (b) Contrast-enhanced coronal T1-weighted MR image shows focal contrast enhancement in the tumour; (c) Axial T2-weighted MR image shows high signal intensity within the mass with lobulated margins; (d) The lesion is of high signal intensity with sharp boundaries on an axial T2-weighted MR image, with little mass effect

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On left temporal craniotomy, the interface between the tumour and normal brain was well-defined. Total resection was achieved. Grossly multiple grayish white gelatinous friable tissue was evident. Histological evaluation disclosed two distinct morphologies with a sharp demarcation between tumour and normal cerebral cortex. The predominant component was complex form of DNET. It showed glioneuronal element composed of oligodendroglioma-like cells (OLCs), astrocytes and mature neurons. OLCs and astrocytes were arranged in trabecular pattern. OLCs contain uniform round dark nuclei with clear perinuclear halos. Floating neurons (ganglion cells) were seen in mucinous matrix [Figure 2]. Coexistent cortical dysplasia was not evident. Transitional zone between loose cystic area of DNET and more cellular area of PA was seen. The minor astrocytic component (approximately 15% of the total tumour bulk) showed fibrillated spindled Piloid cells with oval hyperchromatic, enlarged nuclei. Occasional Rosenthal fibers and granular bodies suggest PA. Mitotic activity was absent [Figure 3]. Immunohistochemistry showed positivity for glial fibrillary acidic protein (GFAP) in the astrocytes but not in the OLCs and ganglion cells. OLCs are strongly immunoreactive with antibodies against S-100-Protein [Figure 4]. Pathological diagnosis of DNET with PA was made.
Figure 2: Dysembryoplastic neuroepithelial tumour: (a) Sharp demarcation between tumour (lower) and normal cerebral cortex (upper) is seen (H and E, ×10); (b) Glioneuronal element in a partially microcystic background (H and E, ×10); (c) Oligodendrocyte-like tumour cells (OLCs) and astrocytes are arranged in trabecular pattern. OLCs contain uniform round dark nuclei with clear perinuclear halos. (H and E, ×40); (d) Mature neurons (ganglion cells) floating in a mucinous matrix (H and E, ×40)

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Figure 3: Dysembryoplastic neuroepithelial tumour with pilocytic astrocytoma: (a) Transitional zone between loose cystic area of DNET (upper-right) and more cellular area of PA (lower-left) is seen (H and E, ×10); (b) The astrocytic component showed fibrillated spindled Piloid cells with oval hyperchromatic, enlarged nuclei with occasional Rosenthal fibers and granular bodies (H and E, ×40)

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Figure 4: Dysembryoplastic neuroepithelial tumour: (a) Immunostain for GFAP highlights the astrocytes but not the oligodendroglia-like cells and ganglion cells (Immunostain, ×40); (b) Small oligodendrocyte-like tumour cells are strongly immunoreactive with antibodies against S-100-Protein (Immunostain, ×40)

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The patient recovered uneventfully. Clinical result of the surgery was excellent. No seizures or tumour recurrence have been observed during five years follow-up.

  Discussion Top

In 1988 Dumas-Duport described the dysembryoplastic neuroepithelial tumour as a rare distinct benign cortical tumour of neuroepithelial origin. They considered the DNET to be at least partially neoplastic and formed during embryonic development from secondary germinal layer.[1],[3],[13] Malignant transformation and regrowth following subtotal resection supports the hypothesis of neoplastic origin.[5],[7],[8],[10] Till date only two cases of PA arising in association with DNETs are reported.[1],[2]

DNETs are most commonly seen in temporal lobe of cerebral cortex.[1],[2],[3],[4],[14] Occasionally DNET has been found in caudate nucleus, septum pellucidum, brainstem and cerebellum.[2],[4] Occasional multifocal DNETs are associated with neurofibromatosis, XXY syndrome and intradural spinal lipoma.[11] DNET usually occur in 6-20 years of age range. Males are affected more frequently than females.[4] Review of literature suggest that development of pilocytic astrocytoma, recurrence and malignant transformation occurs mainly in childhood and young age with predilection to temporal and frontal cortex.[1],[2],[5],[7],[8],[9],[10] Intracranial hypertension and neurologic deficits are not common with DNETs.[4],[14] The signs of raised intracranial pressure suggest malignant transformation.[1] On computed tomography DNETs are typically well-demarcated, hypodense cortical lesions. MR images often show a solid and cystic mass. The solid components often appear multinodular, hypointense on T1-weighted MR images, hyperintense on T2-weighted MR images, and occasionally weakly enhancing.[1],[2],[11],[13] In our case, the clinical and radiological features were not entirely specific to DNET; dilemma occurs between DNET and low grade astrocytoma.

Histologically DNET divided into a simple, complex and non-specific form. The simple form consists of only glioneuronal elements without multinodular architecture. The complex form consists of glioneuronal elements, multinodular architecture, and associated cortical dysplasia. The nonspecific form has neither glioneuronal elements nor the multinodular architecture. It resembles a low-grade astrocytoma but has clinical and radiological features more consistent with a DNET.[4],[13],[14],[15] Occasional DNET may show presence of increased cellularity, pleomorphism, cytological atypia, microvascular proliferation, calcification, necrosis, high MIB-1 labeling indices and extensive involvement of surrounding structures.[1],[3],[4],[10],[11],[13],[15] Theoretically, overgrowth of any components of DNET may result in an independent tumour.[1] However, commonly associated secondary neoplasm with DNETs are PA, anaplastic astrocytoma and glioblastoma suggesting that astrocytic component has more proliferative potential than other component of DNET.[1],[2],[7],[8],[13] DNET with unresected, incompletely resected or even completely removed tumour can show development of pilocytic astrocytoma, recurrence or malignant transformation over a period of 3-11 years.[1],[2],[5],[6],[7],[8],[9] The combined mutagenic effects of radiotherapy and chemotherapy may cause or accelerate the malignant transformation.[8] In all cases of DNET with PA, recurrence and malignant transformation common factor is subtotal excision of tumor and it is probably the major risk factor for the unstable behaviour of DNET in such cases. These might serve as a warning for considering this entity as totally benign.[1],[2],[5],[6],[7],[8],[9] In our case we think that unresected long standing DNET made suitable condition for overgrowth of astrocytic component within the DNET itself.

DNET must be differentiated from low grade gliomas especially oligodendrogliomas, mixed oligo-astrocytomas or astrocytomas in order to avoid unnecessary post surgical radiotherapy or chemotherapy.[3],[4]

Natural history of DNET is not yet completely defined.[2],[13] DNET appear to be remarkably stable in terms of biologic behavior.[13] Complete surgical resection without any adjuvant radiotherapy or chemotherapy is recommended treatment as it gives excellent control of seizures.[2],[4],[8],[11],[12],[13] However, long term follow-up is required because majority of recurrence and malignant transformation occurs after 3 years.[1],[2],[5],[6],[7],[8],[9] Our patient had neither undergone previous surgery nor received any adjuvant therapy and hence this case is a de novo development of PA in a DNET.

  Conclusion Top

DNET is a rare mixed neuroepithelial tumour of younger patients who present with refractory seizures. The early recognition of DNET is important as it has an excellent prognosis on complete surgical excision without use of adjunct therapies. Unresected or incompletely removed DNET and secondary radio-chemotherapy may give rise to recurrence and malignancy. Most common secondary neoplasm is astrocytic in origin. The development of the secondary neoplasm challenges the stability in terms of biological behaviour and highlights the importance of complete surgical excision and close follow up.

  References Top

Zakrzewski K, Biernat W, Liberski PP, Polis L, Nowoslawska E. Pilocytic astrocytoma as a predominant component of a recurrent complex type DNT. Folia Neuropathol 2009;47:284-8.  Back to cited text no. 1
Josan V, Smith P, Kornberg A, Rickert C, Maixner W. Development of a pilocytic astrocytoma in a dysembryoplastic neuroepithelial tumor. Case report. J Neurosurg 2007;106(Suppl 6):509-12.  Back to cited text no. 2
Daumas-Duport C. Dysembryoplastic neuroepithelial tumours. Brain Pathol 1993;3:283-95.  Back to cited text no. 3
Chawla N, Kudesia S, Acharya S, Kumar R, Kishore S, Azadb R. Dysembryoplastic neuroepithelial tumour-A case report. Revista Española de Patología 2011;44:123-6.  Back to cited text no. 4
Maher CO, White JB, Scheithauer BW, Raffel C. Recurrence of dysembryoplastic neuroepithelial tumor following resection. Pediatr Neurosurg 2008;44:333-6.  Back to cited text no. 5
Nolan MA, Sakuta R, Chuang N, Otsubo H, Rutka JT, Snead OC 3rd, et al. Dysembryoplastic neuroepithelial tumors in childhood: Long-term outcome and prognostic features. Neurology 2004;62:2270-6.  Back to cited text no. 6
Hammond RR, Duggal N, Woulfe JM, Girvin JP. Malignant transformation of a dysembryoplastic neuroepithelial tumor. Case report. J Neurosurg 2000;92:722-5.  Back to cited text no. 7
Rushing EJ, Thompson LD, Mena H. Malignant transformation of a dysembryoplastic neuroepithelial tumor after radiation and chemotherapy. Ann Diagn Pathol 2003;7:240-4.  Back to cited text no. 8
Ray WZ, Blackburn SL, Casavilca-Zambrano S, Barrionuevo C, Orrego JE, Heinicke H, et al. Clinicopathologic features of recurrent dysembryoplastic neuroepithelial tumor and rare malignant transformation: A report of 5 cases and review of the literature. J Neurooncol 2009;94:283-92.  Back to cited text no. 9
Schittenhelm J, Mittelbronn M, Wolff M, Truebenbach J, Will BE, Meyermann R, et al. Multifocal dysembryoplastic neuroepithelial tumor with signs of atypia after regrowth. Neuropathology 2007;27:383-9.  Back to cited text no. 10
Khaled A, Joarder A, Chandy M, Nasir TA. Dysembryoplastic neuroepithelial tumour: A case report. Pulse 2010;4:43-4.  Back to cited text no. 11
Chan CH, Bittar RG, Davis GA, Kalnins RM, Fabinyi GC. Long-term seizure outcome following surgery for dysembryoplastic neuroepithelial tumor. J Neurosurg 2006;104:62-9.  Back to cited text no. 12
Garrett M, Eschbacher J, Nakaji P. Dysembryoplastic neuroepithelial tumor: A review. Barrow Quarterly 2008;24:9-13.  Back to cited text no. 13
Daumas-Duport C, Varlet P, Bacha S, Beuvon F, Cervera-Pierot P, Chodkiewicz JP. Dysembryoplastic neuroepithelial tumors: Nonspecific histological forms-a study of 40 cases. J Neurooncol 1999;41:267-80.  Back to cited text no. 14
Prayson RA, Morris HH, Estes ML, Comair YG. Dysembryoplastic neuroepithelial tumor: A clinicopathologic and immunohistochemical study of 11 tumors including MIB1 immunoreactivity. Clin Neuropathol 1996;15:47-53.  Back to cited text no. 15


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

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