Case Review
Volume 5, No.1
April 2001
 Mohamed Z Boudawara(1)
 Jamel Daoud(2)
 Tahia  Boudawara(3)
 Riadh Rebai(1)
 Hafedh Ben Ali(1)
 K Bahloul(1)
 Mounir Frikha(4)
 Rachid Jlidi(3)
 Habib Ben Mansour(1)
 (1) Dept. of Neurosurgery
 (2) Dept. of Carcinology
     Radiotherapy
 (3) Dept. of Cytopathology
 (4) Dept. of Medical      Carcinology
 H Bourguiba Hospital Sfax  Tunisia
 Correspondence:
 Dr. Mohamed Z Boudawara
 Department of Neurosurgery
 H Bourguiba Hospital
 3029 Sfax
 Tunisia
 Fax: (216) 4 243 427
 E-mail: habib.benmansour@rns.tn 
Supratentorial primitive neuro-ectodermal tumours in children

ABSTRACT

Supratentorial primitive neuroectodermal tumours are highly malignant neoplasms that represent 2.8% of all central nervous system tumours. We report 5 cases under 15 years of age who complained of intracranial hypertension syndrome. On scanning, the lesion was large, well demarcated with cystic, solid and calcic components. All patients were operated. Immunocytochemical studies showed that most lesions (4/5) exhibited some degree of differentiation toward neuronal elements. Three patients died. Two survived after surgery and cranio-spinal irradiation. Survival was correlated with the age of the patients and the radiotherapy.

Keywords: Supratentorial primitive neuroectodermal tumours, immuno-cytochemistry and radiotherapy.

INTRODUCTION

The term primitive neuroectodermal tumour (PNET) was introduced for the first time by Hart and Earle in 1973 to designate tumours made of small developed cells in the central nervous system, in the eyes and the riddled blade of the ethmoidal bone.7 Supratentorial PNET are rare and their cytopathological diagnosis is sometimes difficult even by immunocytochemistry.

MATERIALS AND METHODS

Between 1992 and 1998, five patients affected with supratentorial PNET were processed and followed at the hospital of Sfax (Tunisia). There were 3 boys and 2 girls. Average age was 7½ years with extreme years, 2½ and 13 years. Clinical presentation was dominated by a syndrome of intracranial hypertension in 4 patients. A motor deficit was present in 3 cases (Table 1). The topography of the lesion was determined by CT scan for 3 patients and by MRI for the other two. The tumour was, in all cases, large and presented a triple component: fleshy, cystic and calcified (Fig. 1). Four patients underwent total resection and one patient had a biopsy only. The cytopathological examination in 5 cases found small undifferentiated round cells proliferation within a fibrillary background (Fig. 2). These cells were disposed in patternless sheet presenting in some places as Hormer Wright rosettes (4 cases). Areas of necrosis were present in all cases.
In our first observation, the initial diagnosis, without immunohistochemical study, was that of an anaplastic astrocytoma. This diagnosis was suggestive of a recurrence. For the second patient, the immunohistochemical study was negative despite a very sgestive morphological aspect. In the other cases, the diagnosis of PNET suggestive at light microscopy was confirmed by immunocytochemical study (Table 2). Post-operative radiotherapy was given to three patients. It was limited to the encephalon in the case of the first case where the diagnosis of astrocytoma was initially made. The volume targets had comprised the cerebrospinal axis in a dose of 30 Gy (1.8 Gy/session, 5 sessions by week), with a complement of 25 Gy to the tumoural bed according to the same division for patients (Cases 4 and 5). The outcome was favourable for the latter with a regression for 2 and 4 years. The two older children of less than 3 years (Cases 2 and 3) have had initially only a surgical procedure. The outcome was immediately unfavourable for one of them with a post-operative death. The second has presented with an early local relapse after 5 months of evolution; he had presented with an epileptic attack which was fatal. For patient No. 1, the evolution was marked by a local relapse and a secondary spinal location. Two years after the initial procedure, a definitive treatment comprising surgery and spinal radiotherapy was followed by chemotherapy with Etoposide and Cisplatyl. A second relapse occurred 3 years later (Table 1).



Figure 1
Figure 1 - MRI, axial view; huge right temporal lesion, fleshy, cystic and calcified (Patient No. 4) .


Figure 2
Figure 2 - Small round cells with hyperchoromatique nuclei (Patient No. 1)

Table 1 - Epidemiological, clinical, therapeutic and evolutive characteristics of the 5 patients
Case No.
Age (years)
Sex
Location
Signs
Treatment
Evolution
1
7 ½
F
 T-P left ICHT Surgery + encephalic RT Local and spinal recurrence (after 2 years) RT + CT (recurrence after 3 years) Survival time = 5 years
2
2 ½
F
 T-P-O overflowing the medial line ICHT, hemiparesis Surgery Immediate post-operative death
3
3
M
 T right ICHT Surgery In situ recurrence ( 5 months) Fatal issue
4
13
M
 T-P right Hemiparesis Surgery + cerebrospinal RT (30/55 Gy) Complete remission:
4 years
5
12
M
 Frontal right ICHT facial paresis Surgery + cerebrospinal RT (30/54 Gy) Complete remission:
2 years
(ICHT) intracranial hypertension; (RT) radiotherapy; (CT) chemotherapy; (T) temporal; (P) parietal; (O) occipital; (M) male; (F) female


Table 2 - Immunohistochemisty of the 5 patients
Markers observations
NSE
Synaptophysine
PS 100
EMA
Vimentine
GFAP
1
+
+
ND
ND
ND
-
2
-
ND
ND
ND
-
-
3
+
-
-
-
ND
-
4
+
ND
+
+
ND
-
5
+
+
+
+
ND
-
(ND) not done; (+) positive; (-) negative
DISCUSSION

PNET comprise what was formerly, medulloblastoma, cerebral neuroblastoma, medulloepithelioma, pinealoblastoma, ependymoblastoma and olfactory neuroblastoma.16 It comprises of highly crafty tumours developed from primitive germinal cells of the embryonic neural tube.14 They have comparable morphological characters to those of the cerebellar medulloblastoma.16 Supratentorial PNET are rare and represent 2.8% of cerebral tumours.12 They occur essentially in the course of the first decade of life.8,10 They are rarely observed with adolescents or adults.12,14 Two of our patients were respectively 12 and 13 years old. PNET are generally hemispheric seat and lobar.4,5 They are rarely deeply located.4 The tumour was large and lobar in all our patients and overflowing on the median line in one (Case 2). The mode of beginning is often progressive. The period of diagnosis is from 3 weeks to 5 months.5,10 The clinical presentation is dominated by the syndrome of intracranial hypertention.5,9,13,15 Radiological signs are not specific of PNET. The diagnosis is evoked on a beam of clinico-radiological arguments. Typically a supratentorial PNET presents on the CT scan as a large lesion that comprises often one or several cystic cavities, zones of necrotic or haemorrhagic modifications and furnaces of calcifictions.9,4,15 The intensive contrast enhancement to the CT scan or to the MRI reflects the hyper vascularity of the lesion.14 The diagnosis of PNET is histopathological. It is evoked ahead of the existence of an undifferentiated small round cell proliferation sometimes organised in rosettes with some areas of necrosis. These aspects are not constant. In the majority of cases, a differentiation in the neuronal sense can be detected by the immunohistochemistry (positivity of NSE, synatophysine and PS 100). In some cases, no differentiation is detected (Case 2). A glial differentiation is predominant in some cases and can pose a differential diagnosis with an anaplastic glioma (Case 1).4,6,13,15 Even when the surgical excision is complete, it must always be followed by radiotherapy and/or chemotherapy.1,3,6,14 The irradiation has to aim at the whole of the cerebro-spinal axis to avoid the high risk of the leptomeningeal invasion.1,3,6,14,16 Indeed, a spinal relapse was observed in one of our patients when the volume target was only the tumoural bed. Chemotherapy is indicated especially for children less than 3 years.4,11 The chemotherapy prolong the survival according to Gaffney.6 Nevertheless, the prognosis of PNET is often unfavourable.2,11 The median of survival from diagnosis in the literature is 23 months.4 It is even shorter if the exeresis is incomplete and the child is young.1,3,4

CONCLUSION

Supratentorial PNET constitutes a rare entity amongst intracranial tumours in children. They pose problems of pathological diagnosis and therapeutic constraints especially for children less than 3 years.

REFERENCES

1. Albright AL, Wisoff JH, Zeltzer P, Boyett J, Rorke LB, Stanley P, Geyer JR, Milstein JM: Prognostic factors in children with supratentorial (nonpineal) primitive neuroectodermal tumors. A neurosurgical perspective from the Children’s Cancer Group. Ped Neurosurg 1995, 22: 1-7
2. Ciancirarullo TS, Neves BM, Stavale JN: Supratentorial primitive neuroectodermal tumor. Study of 4 cases. Arq Neuropsiquiatr 1994, 52: 392-395
3. Cohn BH, Zeltzer PM, Boyett JM, Geyer JR, Allen JC, Finlay JL, McGuire-Cullen P, Milstein JM, Rorke LB, Stanley P, et al: Prognostic factors and treatment results for Supratentorial primitive neuroectodermal tumors in children using radiation and chemotherapy: a Children Cancer Group Randomised trial: J Clin Oncol 1995, 13: 1687-1696
4. Dirks PB, Harris L, Hoffman HJ, Humphreys RP, Drake JM, Rutka JT: Supratentorial primitive neuro-ectodermal tumors in children. J Neuro Oncol 1996, 29: 75-84
5. Duffner PK, Cohen ME, Heffner RR, Freeman AI: Primitive neuroectodermal tumors of childhood. An approach to therapy. J Neurosurg 1981, 55: 376-381
6. Gaffeney CC, Sloane JP, Bradley NJ, Bloom HJ: Primitive neuroectodermal tumors of the cerebrum. Pathology and treatment. J Neuro Oncol 1985, 3: 23-33
7. Hart MN, Earle KM: Primitive neuroectodermal tumors of the brain in children. Cancer 1973, 32: 890-897
8. Horten BC, Rubinstein LJ: Primary cerebral neuroblastoma: a clinicopathological study of 35 cases. Brain 1976, 99: 735-756
9. Kingsley DPE, Harwood-Nash DCF: Radiological features of the neuroectodermal tumours of childhood. Neuro Radiol 1984, 26: 436-467
10. Kosnik EJ, Boesel CP, Bay J, et al: Primitive neuro-ectodermal tumors of the central nervous system in children. J Neurosurg 1978, 48: 741-746
11. Mikaeloff Y, Raquin M, Lellouch-Tubiana A, Terrier-Lacombe M, Zerah M, Bulteau C, Habrand J, Kalifa C: Primitive cerebral neuroectodermal tumors excluding medulloblastomas: a retrospective study of 30 cases. Ped Neurosurg 1998, 29: 170-177
12. Miyazawa T, Ueno H, Hatashita S, Yagishita S: “Undifferentitated” cerebal primitive neuroectodermal tumor in young adult – case report. Neurol Med Chir (Tokyo) 1994, 34: 759-762
13. Nishio S, Morioka T, Suzuki S, Hamada Y, Kaneko Y, Fukui M: Supratentorial primitive neuroectodermal tumours: a report of four cases with an unusual clinical course in one patient. Acta Neurochir (Wien) 1998, 140: 207-213
14. Pickuth D, Leutloff U: Computed tomography and magnetic resonance imaging findings in primitive neuro-ectodermal tumours in adults Br J Radiol 1996, 69: 1-5
15. Pigott TJ, Punt JA, Lowe JS, Henderson MJ, Beck A, Gray T: The clinical, radiological and histopathological features of cerebral primitive neuroectodermal tumours. Br J Neurosurg 1990, 4: 287-297
16. Rorke LB, Gilles FH, Davis RL, Becker LE: Revision of the World Health Organization classification of brain tumors for childhood brain tumor. Cancer 1985, 56: 1869-1886

 


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