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PubMed1992

Primitive neuroectodermal tumors after prophylactic central nervous system irradiation in children. Association with an activated K-ras gene.

Three patients had supratentorial malignant brain tumors 7 to 9 years after prophylactic central nervous system (CNS) treatment for acute lymphocytic leukemia or malignant T-cell lymphoma. Therapy was administered at the age of 3 to 8 years and included cranial irradiation (total dose, 1800 to 2400 cGy) and intrathecal methotrexate. The brain tumors had histologic and immunohistochemical features of primitive neuroectodermal tumors (PNET), including neuroblastic rosettes, rhythmic arrangement of tumor cells, and immunohistochemical expression of glial, and in one patient neuronal, marker proteins. Using polymerase chain reaction-mediated DNA amplification from paraffin-embedded tissues and subsequent DNA sequence analysis, an activating point mutation was detected in the K-ras protooncogene in one tumor. This mutation was a G to A transition in position 2 of codon 12, substituting aspartate (GAT) for glycine (GGT). This type of mutation has not been observed before in human brain tumors, but it is frequent in radiation-induced murine lymphomas. These observations suggest that PNET can be induced after completion of the embryonal and fetal development of the human CNS. Oncogene-activating point mutations may represent a pathogenetic mechanism involved in the genesis of radiation-induced brain tumors.

Aspartic Acid↗
PubMed1992

Cutaneous angiosarcoma as a second malignant neoplasm after peripheral primitive neuroectodermal tumor.

Second malignant neoplasms (SMN) in late childhood or young adulthood in individuals who have been successfully treated for an initial malignancy have emerged as a late effect of therapy in survivors of childhood cancer. Although radiation therapy is frequently implicated, chemotherapy with alkylating agents and antimetabolites has also been associated with SMN. Soft tissue sarcomas are among the most frequent primary malignancies complicated by a SMN and account for a majority of nonhematolymphoid SMN. We present the clinical and pathologic findings in a patient who had a peripheral neuroepithelioma (primitive neuroectodermal tumor, PNET) of the soft tissues diagnosed at 17 years of age, was treated with high-dose irradiation and multidrug chemotherapy, and developed an angiosarcoma 14 years later. This case represents an uncommon combination of mesenchymal malignancies in a young patient with an unusually favorable clinical course following the diagnosis of PNET.

Adolescent↗
PubMed1991

Extracranial primitive neuroectodermal tumors. The Memorial Sloan-Kettering Cancer Center experience.

The clinical data of 54 patients (57% males) with extracranial primitive neuroectodermal tumors (PNET) seen over a 20-year period at Memorial Sloan-Kettering Cancer Center were reviewed. The age at diagnosis ranged from 1 month to 81 years (median, 17 years). One PNET arose in a previously irradiated site. One patient had an unaffected identical twin. Primary sites were thoracopulmonary (n = 25), pelvis (n = 12), retroperitoneum or abdomen (n = 10), limbs (n = 5), neck (n = 1), and unknown (n = 1). At diagnosis, epidural extension was present in 13 patients with truncal primaries, and 11 patients had distant metastases. All of the latter died with disease. Progression-free survival (PFS) among the 43 patients with localized tumors (all greater than 5 cm) was 25% at 24 months. Two of 13 patients who relapsed after more than 12 months without therapy were long-term survivors. Patients with localized PNET who had resection of all gross disease within 3 months of diagnosis had a significantly longer PFS (P = 0.0003). Radiation therapy caused tumor shrinkage but was not curative of measurable disease. A dose-response effect was evident with the most commonly used drug, cyclophosphamide. Myeloablative regimens using melphalan (n = 8) or thiotepa (n = 1) with autologous bone marrow rescue were not clearly beneficial. The treatment results favor: (1) early surgical removal, (2) dose-intensive use of drugs active against PNET (especially cyclophosphamide), and (3) radiation therapy to ablate residual microscopic disease.

Adolescent↗
PubMedDate not supplied

Treatment of children with peripheral primitive neuroectodermal tumor or extraosseous Ewing's tumor with Ewing's-directed therapy.

PURPOSE: We report the treatment and outcome of patients with peripheral primitive neuroectodermal tumor (PNET) and extraosseous Ewing's tumor (EOE) using Ewing's-directed therapy, including an ifosfamide and etoposide window. METHODS: Seventeen pediatric patients with peripheral PNET (n = 14) or EOE (n = 3) were enrolled between 1988 and 1992 on our institutional Ewing's protocol. Induction therapy comprised a 9-week "window" of ifosfamide and etoposide, followed by 9 weeks of therapy with cyclophosphamide and Adriamycin (Adria Laboratories, Columbus, OH). Response assessment after 17 weeks was followed by surgery and/or radiotherapy (doses based on tumor size and response to induction), repeat evaluation, and maintenance chemotherapy with alternating courses of vincristine/dactinomycin, ifosfamide/etoposide, and cyclophosphamide/Adriamycin for a total of 45 weeks. RESULTS: At diagnosis, 8 patients had large lesions (>8 cm) and 3 had pulmonary metastases (1 with large tumor). Surgical resection was performed at diagnosis for 9 patients and after induction therapy for 5. During window therapy, all of the 9 evaluable patients responded (8 partial, I objective), and no patient without measurable disease developed disease progression. Responses were maintained or improved during subsequent induction in six of the patients with residual disease. Fourteen patients received local radiotherapy. At 49 to 94 months after diagnosis, 12 patients are disease-free (1 in second remission), 4 have died, and 1 is alive with disease. The five-year overall and progression-free survival rates are 77 +/- 13% and 62 +/- 16%, respectively. CONCLUSION: The use of consistent Ewing's-directed combined-modality therapy for patients with soft tissue peripheral PNET/EOE results in survival similar to that of patients with osseous Ewing's tumor. The combination of ifosfamide and etoposide appears active and should be incorporated in future treatment protocols.

Adolescent↗
PubMed1978

Methylcholanthrene induced murine primitive neuroectodermal tumor: ultrastructure and nuclear RNA polymerase activity.

The histology, ultrastructure, and nuclear RNA polymerase activity are described in a murine primitive neuroectodermal tumor derived by serial transplantation from a tumor originally induced with methylcholanthrene and classified as an ependymoblastoma. The light microscope and ultrastructural studies show that this tumor does not contain the distinguishing morphological features of differentiated ependymal cells which are also commonly seen in human ependymomas. One outstanding feature is the size and number of the nucleoli. The mean number of nucleoli/nucleus is 4 which is two to four times that of the normal neuroglial cell. The nucleolar diameter is about twice that found in normal neuroglial cells. The nucleolar diameter is about twice that found in normal neuroglial cells. The nuclear RNA synthesizing activity is the highest of the chemically induced animal tumors we have studied. The alpha amanitin inhibition is the lowest seen in any of these tumors which suggests that RNA polymerases inhibited by alpha amanitin contribute less to the total nuclear RNA synthesis. Adriamycin significantly inhibits the nuclear RNA polymerase activity of this tumor.

Animals↗
PubMed2001

Extraaxial primitive neuroectodermal tumor mimicking a vestibular schwannoma: diagnostic and therapeutic difficulties. Report of two cases.

Extraaxial cerebellopontine angle (CPA) medulloblastomas and other primitive neuroectodermal tumors (PNETs) are rare tumors. The authors report on two patients with PNETs who presented with progressive audiovestibular symptoms. In each case magnetic resonance (MR) imaging revealed an extraaxial lesion that filled the internal auditory meatus and exhibited the neuroimaging features of a vestibular schwannoma (VS). No high signal intensity was apparent in either the brainstem or adjacent cerebellum on T2-weighted MR images. Surgery with maximum resection (total in one case and subtotal in the other) was performed, followed by craniospinal radiotherapy. One year postoperatively, both patients were free from tumor. A CPA PNET mimicking a VS is a rare entity, the diagnosis of which is important because its treatment differs dramatically from that of VS, including prescribed surgery followed by conventional craniospinal radiotherapy.

Adult↗
PubMed1994

Cerebellar dysplasias in humans: development and possible relationship to glial and primitive neuroectodermal tumors of the cerebellar vermis.

Cerebellar dysplasias are commonly found in the white matter and nodulus of the vermis in newborns and are particularly prominent in infants with trisomy 13-15 and trisomy 18 syndromes. Little is known of the developmental biology of these structures. We have studied the development of cerebellar dysplasias in human fetuses ranging from 15 to 32 weeks gestational age and from 11 days to 15 months postnatal. The expression of developmentally regulated neuronal and glial polypeptides was investigated by immunohistochemistry using a panel of extensively characterized monoclonal antibodies. Dysplasias were first observed at 15 weeks gestation as irregularly distributed, parenchymal or perivascular clusters of primitive cells in the inferior vermis. These cell clusters resembled primitive neuroepithelial cells or cells of the cerebellar external granule cell layer and they persisted into postnatal life. They retained the capacity to undergo cell division and were weakly reactive for the low affinity nerve growth factor receptor but were negative for all other neuronal or glial proteins at all gestational ages. At about 20 weeks gestation, cerebellar dysplasias become more complex with the appearance of ganglion cells which matured histologically and phenotypically in parallel with normal dentate neurons and Purkinje cells. These dysplasias often contained a prominent glial component which was identified by immunostaining for glial fibrillary acidic protein. Our findings suggest that midline cerebellar dysplasias are normal variants of development. Whether the mitotically active cells comprising these dysplasias are targets for neoplastic transformation into cerebellar primitive neuroectodermal tumors or other types of childhood tumors such as pilocytic astrocytomas or atypical teratoid/rhabdoid tumors remains speculative.

Abortion, Therapeutic↗
PubMedDate not supplied

Primitive neuroectodermal tumor in the cerebellopontine angle with isochromosome 17q presenting as meningioma in a woman 26 years of age.

An unusual posterior fossa neoplasm in a 26-year-old woman with short history of the cerebellar symptoms is presented. CT and MR images showed the tumor within the cerebellopontine angle, suspected as meningioma. At surgery, the tumor was dura-attached and did not infiltrate the arachnoid. Histologically, the neoplasm was a small blue cell tumor with solid and microcystic pattern, consistent with primitive neuroectodermal tumor (PNET). Immunohistochemically the cells were strongly positive for NCAM and GFAP. Fluorescence in situ hybridization (FISH) was performed with the cosmids G9 and F7 (flanking EWSR1/22q12 region) DNA probes and dual-color spectrum-orange LSI HER-2/neu (17q11.2)/spectrum green CEP17 (17p11.1-q11.1) DNA probe. The presence of isochromosome 17q within neoplastic cells was found. The tumor was classified as a medulloblastoma. We demonstrate the utility of a multidisciplinary approach to nervous system tumor diagnosis. The clinical features together with histological, immunohistochemical, and characteristic molecular alteration allowed classification of the presented case.

Adult↗
PubMed2003

Primitive neuroectodermal tumor of the mandible: report of a rare case.

We describe what we believe is only the second reported case of primitive neuroectodermal tumor of the mandible. Our patient was successfully treated initially with surgery and adjuvant radiation and chemotherapy, but 18 months later she developed a fatal pulmonary metastasis. Although this tumor is aggressive and prone to recurrence and metastasis, early intervention might improve the prognosis in affected patients. In patients with unresectable disease, radiation and chemotherapy might have palliative value.

Adult↗
PubMed1997

Long-term survival in an adult metastatic renal peripheral primitive neuroectodermal tumor (PPNET) with multimodality treatment including high-dose chemotherapy.

We describe a 42-year-old male patient with a primitive peripheral neuroectodermal tumor (PPNET) arising from the kidney. The patient was treated sequentially with surgery, radiotherapy, experimental cytokine treatment (rhIL-6), combination chemotherapy and consolidated in complete remission with high-dose chemotherapy, supported by autologous stem cells (AST) and hematopoietic growth factors. The patient remains in complete remission at 34+ months after AST and is surviving disease-free for five years after initial presentation. The case presented here is unusual because of the renal origin and the long remission duration and survival when compared with the usual outcome of adult metastatic PPNET. High-dose chemotherapy may have favorably influenced the outcome in this patient. The case is discussed in the context of the general treatment of metastatic PPNET.

Adult↗
PubMed2002

Fine needle aspiration cytology in the diagnosis and management of children and adolescents with Ewing sarcoma and peripheral primitive neuroectodermal tumor.

PURPOSE: The utility of fine needle aspiration cytology (FNAC) in conjunction with immunocytochemistry in the diagnosis of Ewing sarcoma and peripheral primitive neuroectodermal tumor, the Ewing family of tumors (EFT), is retrospectively described. PATIENTS AND METHODS: During a 10-year period 24 children and adolescents were diagnosed at Karolinska Hospital to have EFT of bone or soft tissue using FNAC. Criteria for diagnosis was based on cytomorphology combined with immunocytochemistry. The median age was 14.1 years (range 0.7-20.2). FNAC was performed within a median time of 1 day after referral. RESULTS: Forty aspiration procedures were performed, 24 at primary work up in 23 patients and 16 at suspected relapses in 10 patients. A primary cytologic diagnosis of EFT was obtained in 22 of 23 cases. In nine cases with primary disease there was no histologic confirmation. Two tumors were on FNAC diagnosed as neuroblastoma versus EFT, and EFT, respectively. Histopathology on resected tumor tissue from these patients showed EFT and small cell osteosarcoma, respectively. Suspected relapse was found to be positive at five and negative at 11 occasions. Immunocytochemistry was positive for CD45 (LCA) in 0/12, for desmin in 2/21, for MIC2 in 15/15, for NB84 in 1/3, for NFP in 7/7, for NSE in 12/18, for S-100 in 4/11 and for vimentin in 18/19. CONCLUSIONS: The results show that FNAC together with immunocytochemistry is a rapid, physically atraumatic and accurate method in diagnosing both primary EFT of bone and soft tissue as well as relapses.

Adolescent↗
PubMed1992

Primitive neuroectodermal tumor arising in the skin. Differentiation from neuroendocrine carcinoma of the skin.

We report a 25-year-old male patient with primitive neuroectodermal tumor presenting as a subcutaneous tumor on the right buttock, which was initially diagnosed as neuroendocrine carcinoma of the skin. Subsequently, local recurrence and metastatic spread to the lung occurred. The tumor was resistant to highly aggressive chemotherapy. The patient died 6 months later with severe pulmonary and lymph node involvement.

Adult↗
PubMed2000

Primitive neuroectodermal tumors of the brainstem: investigation of seven cases.

OBJECTIVE: We discuss the clinical aspects, pathology, and molecular genetics of 7 patients with primitive neuroectodermal tumors (PNETs) arising in the brainstem that were treated at our institution from 1986 through 1995. Most neuro-oncologists avoid performing biopsies in children with pontine tumors. This article raises the question as to whether biopsies should be performed, because treatment recommendations might differ if a PNET was diagnosed rather than a pontine glioma. PATIENTS AND METHODS: We reviewed the clinical neuro-oncology database and the files of the Division of Neuropathology at New York University Medical Center from 1986 through 1995 and identified 7 histologically confirmed PNETs arising in the brainstem among 146 pediatric brainstem tumors. The clinical, neuroradiological, and neuropathological data were reviewed. Postmortem examinations were performed in 2 cases. Formalin-fixed, paraffin-embedded tumor tissues were also available in 6 of 7 patients that were tested for p53 gene mutations using single-strand conformation polymorphism analysis. We also tested 9 cerebellar PNETs, 9 brainstem gliomas, and 3 normal brains for p53 gene mutations as controls. RESULTS: All 7 patients presented with focal cranial nerve deficits, and 2 were also hemiparetic. The median age at diagnosis was 2.7 (1-8 years). Magnetic resonance imaging (MRI) characteristics included a focal intrinsic exophytic nonenhancing brainstem lesion that had low T1-weighted and high T2-weighted signals. Hydrocephalus was present in 5 patients at diagnosis, 3 of whom had leptomeningeal dissemination. Meningeal dissemination occurred later in the course of the disease in 3 other patients. Five children required shunts at diagnosis and another 2 at recurrence. Despite therapy, all 7 PNET patients died within 17 months of diagnosis with a mean survival of 8 (4-17) months. No mutation in the p53 gene was detected. CONCLUSIONS: Brainstem PNETs tend to arise at a younger age than brainstem gliomas and medulloblastomas. The MRI pattern suggests a localized rather than a diffuse intrinsic nonenhancing brainstem tumor. Like other PNETs, brainstem PNETs have a high predilection to disseminate within the central nervous system. The absence of p53 mutations is similar to other PNETs. Despite their origin close to the cerebellum, brainstem PNETs exhibit a more aggressive behavior and result in worse clinical outcomes than do cerebellar PNETs.

Brain Neoplasms↗
PubMed2006

Quantitative mRNA expression analysis of neurotrophin-receptor TrkC and oncogene c-MYC from formalin-fixed, paraffin-embedded primitive neuroectodermal tumor samples.

Most recent studies analyzing candidate biological prognostic factors (including neurotrophin receptor TrkC and proto-oncogene c-MYC) in childhood primitive neuroectodermal brain tumors (PNET) are limited by small patient numbers due to dependence on fresh-frozen tumor material. In contrast, large archives of formalin-fixed, paraffin-embedded PNET samples exist from homogeneously treated patients. The ability of real-time RT-PCR to assay very small mRNA fragments makes this assay amenable to studies where the RNA is moderately or even highly degraded. We have optimized RNA isolation from archive PNET samples and found that TrkC and c-MYC mRNA measurements significantly correlated with those obtained from matching fresh-frozen tissues. Exploitation of already existing archives of formalin-fixed paraffin-embedded PNET samples may accelerate the building of better stratification systems for PNET patients.

Adolescent↗
PubMed1994

EWS-erg and EWS-Fli1 fusion transcripts in Ewing's sarcoma and primitive neuroectodermal tumors with variant translocations.

We have determined the frequency of EWS fusion transcripts in a series of primary Ewing's sarcomas and peripheral primitive neuroectodermal tumors and cells lines. Type 1 and 2 EWS-Fli1 fusions were demonstrated in 8 cell lines and 14 patient samples. Five patients with cytogenetically characterized rearrangements of chromosome 22 that did not involve chromosome 11 were included in these studies. A novel EWS-Fli1 in-frame isoform fusing EWS to exon 8 of Fli1 was isolated from a tumor with a variant t(12;22;22)(q14;p1;q12) translocation. Three in-frame isoforms of a novel hybrid transcript derived from the fusion of EWS with the ETS domain of the human erg gene were identified in patient samples and a cell line with cytogenetically unidentified or cryptic translocations involving chromosomes 21 and 22. Interphase analysis by fluorescent in situ suppression hybridization using two overlapping erg yeast artificial chromosome clones demonstrated disruption of the erg gene on chromosome 21 in a patient sample with monosomy 22. Our results provide new information about the involvement of EWS in small round cell tumors involving exchange of its putative RNA-binding domain with DNA-binding domains derived from different members of the ETS family of transcription factors. These studies emphasize the utility of reverse transcriptase PCR analysis and fluorescent in situ hybridization as additional diagnostic tools for differential diagnosis among small round cell tumors.

Adolescent↗
PubMed1994

Hyperfractionated craniospinal radiation therapy for primitive neuroectodermal tumors: early results of a pilot study.

PURPOSE: To report the early results of hyperfractionated craniospinal radiation therapy with and without adjuvant chemotherapy for primitive neuroectodermal brain tumors (PNETs). METHODS AND MATERIALS: Thirty-nine patients with PNETs were classified as good-risk (23) or poor-risk (16), based on postoperative magnetic resonance imaging and a cytological examination of cerebrospinal fluid. All patients received hyperfractionated craniospinal radiation therapy; poor-risk patients subsequently received adjuvant chemotherapy with cisplatin, lomustine, and vincristine. The first six patients received 72 Gy to the primary tumor site and 24 Gy to the rest of the craniospinal axis. Subsequent patients received 30 Gy to the craniospinal axis. RESULTS: During a median of 1.9 years of follow-up (range 4 months to 3.5 years), there have been ten treatment failures in 39 patients, five in the good-risk group and five in the poor-risk group. Three failures occurred in the primary tumor site in areas that received 72 Gy; two were in poor-risk patients with residual disease after surgery; one was in a good-risk patient who had a gross total resection. Three failures occurred in the spine and craniospinal fluid of patients treated with 24 Gy. Four occurred in areas treated to 30 Gy; two of these were in areas thought to be undertreated because of treatment planning errors. Adjuvant chemotherapy was difficult to give to poor-risk patients because of poor bone marrow recovery, even with relatively low doses of lomustine (75 mg/m2). CONCLUSION: We think a dose of 24 Gy to the craniospinal axis is inappropriate because three of the six patients who received it had treatment failures outside the primary site. Whether 30 Gy is an appropriate dose for good-risk patients is still unclear. Even after a dose of 30 Gy, chemotherapy was difficult to give; this potentially limits the impact of adjuvant chemotherapy in poor-risk patients. Further follow-up is necessary to evaluate the use of hyperfractionated radiation therapy alone or with chemotherapy in patients with PNETs.

Adolescent↗