Primitive Cerebral Neuroectodermal Tumors Excluding Medulloblastomas: A Retrospective Study of 30 Cases

Abstract

We present a retrospective study of 30 cases of primitive cerebral neuroectodermal tumors (PNET), excluding medulloblastomas, referred to us postoperatively for additional therapy to evaluate prognostic factors and treatment efficiency. The histologic types were: pinealoblastomas (n = 7); ependymoblastomas (n = 2); medulloepitheliomas (n = 4), and other PNET (n = 17). The tumor was located in the supratentorial area in 24 patients and in the posterior fossa in 6 patients. Among the supratentorial tumors, 8 were metastatic. Maximal surgical resection was performed. Sixteen of 30 patients had no measurable disease after surgery and were considered as standard-risk (SR) cases, and 14 with a local residue or metastasis as high-risk (HR) cases. The objective of postsurgical treatment was to avoid radiotherapy in children below 4 years of age. It consisted of radiotherapy alone in 6 patients, chemotherapy alone in 17, and radiotherapy with chemotherapy in 7. Furthermore, high-dose chemotherapy (busulfan, thiotepa) and autologous bone marrow transplantation, performed in 6 patients, yielded a response rate of 3/6. Event-free survival (EFS) of SR patients was 37% at 3 years (95% confidence interval (CI) 14–60%) and overall survival 44% (95% CI 26–62%). Only 1 of the HR patients achieved a complete remission and all of them died early. The critical prognostic factors appear to be the completeness of initial surgical resection and absence of metastasis. These tumors have a poor prognosis. Novel strategies (high-dose chemotherapy) are needed to improve their outcome because the children concerned are very young and the effects of radiotherapy are particularly deleterious when tumors are situated in the supratentorial area.

Supratentorial primitive neuroectodermal tumor in an adult: a case report and review of the literature

“…Even though no prospective treatment studies have been conducted to date, and no optimal treatment regimen for sPNET has been established, a complete surgical excision followed by radiation therapy has been proved to be crucial in many retrospective studies [9-12]. Radiotherapy to the entire neuroaxis is recommended because cerebrospinal dissemination at the time of diagnosis was found in almost 10% of all cases.…”

Cerebral Medulloepithelioma With Long Survival -Case Report-

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][42][43][44][45] Although most medulloepitheliomas manifest in the first decade of life, 1,11,13,15,22,25,28,31,39,40,…”

“…1,6,10,11,21,22,28,31,38,40,44) On the other hand, intraorbital, 7,8,15,30) peripheral, 26) and cauda equina 22) medulloepitheliomas have a much less malignant course and even those treated primarily or only by enucleation tend not to recur for a long time. 7,15,19,27) Extracranial and intracranial medulloepitheliomas have similar histological features, 8,30) and the great difference in the prognosis remains to be elucidated. In addition, the differences in the biological characteristics and behaviors of these neoplasms are unexplained.…”

Primitive neuroectodermal tumor of the orbit in a 5-year-old girl with microphthalmia

“…The classical initial treatment for PNET, in general, is surgery [21]. Successful treatment requires the use of multidrug chemotherapy in addition to surgery [22].…”