1. Case Presentation
Int 張修碩

2. Patient information Name：林X純 Age：26 y/o Gender：Female ID NO.：05869792
ESRD s/p CAPD for 8 years

3. Brief History -I Lower back pain with radiation to R’t leg for 2 weeks
She visited our OPD and ER for help several times
L-spine MRI on 90/10/22  L3-4 intradural 4cm mass, dumbbell shape
1st C/T:90/12/3(MOE)
2nd C/T:91/1/3

4. T1WI
+GD
T2WI

5. Brief History -II
L2-4 laminectomy and excision of intraspinal tumor on 90/11/13
 Primitive neuroectodermal tumor (PNET)
MRI on 90/11/19, s/p op  Susp residual tumor along the nerve root of L2-3 and tumor seeding at conus medullaris, no measurable mass was found

6. Brief History -III
Brain MRI on 90/11/30  No definite focal lesion in the brain parenchyma nor abnormal enhancement
C/T with (Oncovin + Epirubicin + Ifosphamide) x 2 on 90/12/3 & 91/1/3, at least partial remission
Severe toxicity from C/T  shift to R/T

7. Brief History -IV
R/T from 91/2/27 to 91/4/2 L1 to L5：4500 cGy / 25 friction / 34 days
MRI of L-spine on 91/5/8  Granulation or calcification left behind at the original intradural PNET of L3 level
Gallium-67 tumor scan on 91/12/26  No evidence of Gallium-avid tumor  Complete remission!

8. Primitive Neuroectodermal Tumor （PNET）
DISSICION
Primitive Neuroectodermal Tumor （PNET）

9. Introduction -I
1973, Hart and Earle first introduced the term “primitive neuroectodermal tumor”
They described predomainately undifferentiated tumors of the cerebrum which contained 90–95% of undifferentiated cells
Did not fulfill the diagnostic criteria for other tumor entities

10. Introduction -II
10 years later, Rorke and Becker and Hinton independently advocated that all CNS tumors predominantly composed of primitive neuroeptithelial cells should be called PNETs
The concept has been widely accepted that the classification of PNETs is based on their differentiation
Hum Pathol 14(6): 538–550, 1983
J Neuropathol Exp Neurol 42(1): 1–15, 1983

11. Introduction -III
In the most recent WHO classification, PNETs are defined as follows:
an embryonal tumor composed of undifferentiated or poorly differentiated neuroepithelial cells which have the capacity for or display divergent differentiation along neuronal astrocytic, ependymal, muscular or melanotic lines
Pathology and Genetics of Tumors of the Central Nervous System, 2000, pp 141–144

12. Introduction -IV Malignant, small cell, highly cellular neoplasms
PNET of CNS :
Infratentorial (medulloblastoma), cerebellum
21% of all primary brain tumors in children
Supratentorial
Rare, young adult
Age :
75% < 15 y/o
smaller peak in young adults (21-40 y/o)

13. Clinical features No pathognomonic signs or symptoms exist
The onset at presentation is insidious
Altered mental status
Morning headache
Nausea/vomiting
Blurred vision (papilledema)
Truncal ataxia

14. Images CT findings MRI findings
High-density midline mass (highly cellular tumors) on noncontrast CT
Relatively heterogeneous
Variably contrast enhancement
MRI findings
A heterogeneous mass with ill-defined margin arising from the vermis
T1 : hypo- to isointense ; T2 : iso- to hyperintense
Moderate to intense enhancement of the tumor
Hydrocephalus is common

15. Noncontrast CT
Contrast CT

16. T1WI
T1WI + GD

17. Primary intraspinal PNET
Most cases of PNET involving the spinal cord are “drop” metastases from intracrainal tumors
Primary intraspinal PNET is very rare
To date, only 18 cases has been reported in the literature
Neurology India, 50, March 2002

18. Neurology India, 50, March 2002

19. Characteristics of spinal PNET -I
More common in adults rather than children (age 7-56, mean 30.7 years)
Arise at all level of the spin and can be intramedullary, extramedullary, combined intra- and extra-medullaey, as well as extradural
Frequently located at lower spinal levels (6 cases in cauda equina)

20. Characteristics of spinal PNET -II
Lung, bone, lymph node metastasis, a tendency shared with intracrainal PNET
Rapidly growing and poor outcome
Rapid recurrence
The cause of death in these patients included pneumonia, metastatic disease and progressive spinal cord involvement
Median survival was 18 months
40% at 2 yrs after diagnosis, 10% at 3 yrs

21. Images
Postcontrast T1WI
Am J Clin Oncol (CCT), Vol. 25, No. 2, 2002

22. Images
T2WI
T1WI
T2WI
Neurology India, 50, March 2002

23. Treatment -I
Surgery
Due to the high rate of local tumor progression, a maximum tumor resection should be carried out without causing severe neurological damage

24. Treatment -II Radiotherapy
Nearly all reported patients with primary intraspinal PNETs underwent radiation therapy
The impact of radiation therapy on local control is unclear
With regard to the high propensity for intraspinal subarachnoidal spread, it appears reasonable to indicate treatment of the whole neuroaxis

25. Treatment -III Chemotherpay
Half of the patients described above did not undergo C/T as part of their initial therapy
2 of the 3 patients with distant metastases during follow-up had no chemotherapy
Chemotherapy is now a standard therapeutic ingredient in most protocols for children with infratentorial PNETs either prior to or following radiotherapy

26. Conclusion The optimal therapy for PNET is uncertain
Early onset of chemotherapy in conjunction with radiation therapy may improve the survival time
However the prognosis of this disease is very poor and most patients develop local recurrence
Combined with early detection, tumor identification and surgical removal and chemotherapy and aggressive neuraxis radiation, offers hope of long term and good quality survival

27. Thanks for your attention