Case Presentation Int 張修碩

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

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

T1WI +GD T2WI

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

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

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!

Primitive Neuroectodermal Tumor （PNET） DISSICION Primitive Neuroectodermal Tumor （PNET）

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

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

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

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)

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

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

Noncontrast CT Contrast CT

T1WI T1WI + GD

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

Neurology India, 50, March 2002

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)

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

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

Images T2WI T1WI T2WI Neurology India, 50, March 2002

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

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

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

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

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