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PubMedDate not supplied

Cytogenetic and molecular genetic abnormalities in primitive neuroectodermal tumors of the central nervous system.

Primitive neuroectodermal tumors constitute a large class of pediatric brain tumors. Despite notable recent advances in improving treatment and survival, the pathogenesis and the molecular genetic bases of these malignancies remain poorly understood. Combined cytogenetic and molecular genetic approaches have been used to identify genomic alterations in different histologic tumor types. Translation of these advances from basic science to clinical application is currently underway. Goals for the future include the development of more efficacious treatment strategies while simultaneously lessening toxicity. The most important cytogenetic and molecular genetic abnormalities documented to date together with their potential prognostic significance are reviewed.

Aneuploidy↗
PubMed2004

Primitive neuroectodermal tumor (PNET) of the uterine isthmus.

Primitive neuroectodermal tumors (PNETs) of the uterus are very rare. The histogenesis of these tumors is still unknown and the differential diagnosis includes a wide variety of tumor entities. We describe a rare case of a 68-year-old female who presented with persistent vaginal bleeding. Physical examination and CT-scan revealed a large tumor in the uterus. Macroscopically the tumor involved the uterine isthmus. Histological and immunohistochemical examination showed that the tumor fulfilled the diagnostic criteria set for PNET. Only a very small number of cases of PNETs of the uterus have been reported in the literature, thus no definitive conclusions concerning the therapeutic management and prognosis have been ascertained.

Aged↗
PubMed1998

[An operative case of primitive neuroectodermal tumor in the posterior mediastinum].

A primitive neuroectodermal tumor (PNET) is very rare and the prognosis of this tumor is poor. A 32-year-old woman complaining of dysphagia and back pain was admitted to our hospital for the posterior mediastinal tumor. The tumor originated from the muscle layer of esophagus and en bloc resection of the tumor combined with the affected part of esophagus was performed. Histopathological diagnosis of the resected tumor was PNET. She received adjuvant chemotherapy. Eight months after the surgery, recurrent tumors in the right mediastinum and the retrooperitoneal space was resected completely. But after the second surgery, dissemination occurred recurrently. These recurrent tumors revealed high sensitivity for radio-therapy. However, she died of rapid recurrence 22 months after the first surgery. In Japan, our case is the second case of PNET in the posterior mediastinum and the first case of PNET arising from the muscle layer of esophagus.

Adult↗
PubMed2003

Ewing's sarcoma and peripheral primitive neuroectodermal tumor cells produce large quantities of bioactive tumor necrosis factor-alpha (TNF-alpha) after radiation exposure.

PURPOSE: In the present study, we examined human Ewing's sarcoma (ES) and peripheral primitive neuroectodermal tumor (pPNET) cell lines that are able to produce TNF-alpha as part of the response to irradiation. Radiation-induced tumor cell production of TNF-alpha may enhance irradiation efficacy and improve the effect of local tumor irradiation. On the other hand, radiation-induced tumor cell production of TNF-alpha may adversely affect the normal tissue. METHODS AND MATERIALS: Twelve different ES/pPNET cell lines were investigated in vitro and (after establishment as tumor xenografts in athymic nude mice) in vivo for their TNF-alpha mRNA expression (real-time quantitative reverse transcriptase polymerase chain reaction) and TNF-alpha protein production (in vitro: enhanced amplified sensitivity immunoassay; in vivo: immunohistochemistry) after exposure to different irradiation doses (2, 5, 10, 20, 30, or 40 Gy) and after different time intervals (1, 3, 6, 12, 24, 48, or 72 h after irradiation). The bioactivity of the TNF-alpha protein was evaluated in chromogenic cytotoxicity and neutralization assays. RESULTS: Nine out of 12 ES/pPNET cell lines express constitutively significant quantities of bioactive TNF-alpha in vitro. ES/pPNET cells originating from primary tumors secreted higher TNF-alpha levels than cells derived from metastatic lesions. In 5 of the 9 TNF-alpha-producing cell lines, TNF-alpha mRNA and protein levels were upregulated after irradiation exposure in a time- and dose-dependent manner. After establishment of the ES/pPNET cell lines in athymic nude mice, the radiation-induced TNF-alpha release could be demonstrated also in the xenograft tumors in vivo (analogous to the in vitro experiments). Using the same methods for quantitative analysis, it was determined that the TNF-alpha expression of the radiation-responsive tumor cells was up to 2000-fold higher compared to the maximal radiation-induced TNF-alpha release in normal lung tissue measured during the pneumonic phase. CONCLUSION: Certain ES/pPNET cell lines produce extremely large quantities of bioactive TNF-alpha after radiation exposure in a time- and dose-dependent manner. Radiation-induced TNF-alpha production of tumor cells may be of paramount importance in respect to not only tumor behavior, but also to potential damage to normal tissue and the clinical status of the host.

Animals↗
PubMed2006

Renal primitive neuroectodermal tumor in childhood with intracardiac extension.

Primary primitive neuroectodermal tumors of the kidney are exceptionally rare and usually affect children and young adults. We report the first pediatric case of renal primitive neuroectodermal tumor presenting with tumor extension along the inferior vena cava to the right ventricle. This case highlights that when considering a renal tumor with significant intravascular extension in the pediatric age group, although the most likely diagnosis remains Wilms tumor, other rare entities may also demonstrate similar clinical and imaging features.

Child, Preschool↗
PubMed1997

Peripheral primitive neuroectodermal tumor involving the paravertebral and retroperitoneal regions.

A rare case of peripheral primitive neuroectodermal tumor (PNET) is reported. A 68-year-old woman complaining of lumbago was admitted to our hospital. Diagnosis was made based on pathological findings characterized by Homer Wright-type rosettes. Ultrastructural examination showed the presence of neurosecretory granules and short cytoplasmic processes, which were highly suggestive of neural differentiation. Chromosomal analysis of the neoplastic cells revealed translocation (11;22)(q24;q12), which is often found in Ewing's sarcoma and Askin tumor. These results strengthen the hypothesis of a common histogenesis for these small round cell tumors, and suggest common oncogenesis for these neoplasms.

Aged↗
PubMed2004

Primitive neuroectodermal tumor in the jaw: report of a case.

The neuroectodermal tumor is a malignant neoplasm of round cells originated from the neural crest. The occurrence of this tumor in head and neck is rare. A 5 month old Mexican patient with a primitive neuroectodermic tumor stage IV, in the jaw is reported.

Female↗
PubMed2001

Adult neuroblastoma of the retroperitoneum and abdomen: clinicopathologic distinction from primitive neuroectodermal tumor.

Adult neuroblastoma (ANB) is a rare and poorly recognized entity among a histologically defined group of small, round-cell tumors arising in the retroperitoneum and abdomen. Eight cases of ANB were compared with seven cases of primitive neuroectodermal tumor (PNET) in these locations to identify clinicopathologic features that could be used to distinguish between the two lesions. The ANB study group included four men and four women 22-74 years of age (mean 38 years). Five patients with ANB presented with inflammatory symptoms or elevated levels of catecholamines and their metabolites. Five of the ANB tumors were classified as undifferentiated and three as poorly differentiated with a background of neuropil. These cases often showed immunoreactivity for multiple neural markers such as CD56, chromogranin A, synaptophysin, neurofilament, and neuron-specific enolase, but were negative for CD99, cytokeratins, desmin, myogenin, smooth muscle actin, muscle-specific actin, CD34, S-100 protein, and CD45. In contrast, all of the PNETs were positive for CD99, and four (57%) were also positive for cytokeratins. Two cases of ANB of the undifferentiated subtype had ultrastructural features characteristic of neuroblastoma and lacked a chimeric transcript (EWS-FLI1or ERG), which is specific for PNET. All five patients with the undifferentiated subtype of ANB and six of the seven patients with PNET died of their disease within 3 years of discovery of the lesion. Our results show that ANB, although rare, should be considered in the differential diagnosis of patients with small, round-cell tumors in the retroperitoneum and abdomen. Appropriate immunohistochemical studies and laboratory examination enable pathologists to distinguish ANB from other differential diagnoses, especially PNET.

Abdominal Neoplasms↗
PubMed1997

EWS/FLI-1 fusion transcripts in three peripheral primitive neuroectodermal tumors of the kidney.

Although primitive neuroectodermal tumor (PNET) is a well-recognized entity, its renal localization as a primary site has not been appreciated. Only nine cases of renal PNET exist in the literature. The paucity of renal PNET could be explained by the lack of objective diagnostic techniques that would facilitate its distinction from other primitive round cell tumors of the kidney, such as the more widely recognized monophasic Wilms' tumor and clear-cell sarcoma of the kidney (CCSK), as well as renal carcinoid, or neuroblastoma invading the kidney from the adjacent adrenal gland. The recently identified specific fusion transcripts detectable by reverse transcription polymerase chain reaction (RT-PCR) have provided us with a valuable tool for the detection of renal PNET. This article reports three renal PNET that expressed EWS/FLI-1 fusion transcripts by RT-PCR, in addition to positive staining for MIC2 protein and neuron-specific enolase (NSE). One also exhibited dense core granules in cell processes by electron microscopy. Employment of such methodology will lead to a more accurate classification of renal tumors.

12E7 Antigen↗
PubMed2006

Phase II study of oxaliplatin in children with recurrent or refractory medulloblastoma, supratentorial primitive neuroectodermal tumors, and atypical teratoid rhabdoid tumors: a pediatric brain tumor consortium study.

BACKGROUND: An open-label Phase II study of oxaliplatin was conducted to evaluate its safety and efficacy in children with recurrent or refractory medulloblastoma (MB), supratentorial primitive neuroectodermal tumors (SPNET), and atypical teratoid rhabdoid tumor (ATRT). METHODS: Patients were stratified as follows: stratum IA, first recurrence MB with measurable disease; IB, recurrent MB with only cerebral spinal fluid (CSF) positivity or linear leptomeningeal disease (LLD); IC, MB > or =second recurrence; stratum II, recurrent SPNET; stratum III, recurrent ATRT. Patients received oxaliplatin, 130 mg/m(2) intravenously over 2 hours every 3 weeks. The primary objective was to estimate the sustained response rate in stratum 1A. Plasma ultrafiltrate platinum pharmacokinetics were evaluated. RESULTS: A total of 43 patients with a median age of 8.5 years (range, 0.6-18.9 years) were enrolled. In stratum 1A, 2 of 15 had partial responses (PRs, 1 sustained PR). No responses were observed in other strata. The most frequent Grade 3 and 4 toxicities included thrombocytopenia (25.6%), neutropenia (16.3%), leukopenia (12%), increase in serum alanine transaminase (ALT) (7%), vomiting (4.7%), and sensory neuropathy (4.7%). No severe ototoxicity or nephrotoxicity was reported. Plasma ultrafiltrate platinum pharmacokinetic parameters were similar to adults, with a median clearance of 12.2 L/hr (range, 4.4-30 L/hr) and median area under the curve (AUC(0-infinity)) of 9.4 microg/mL/hr (range, 6.2-13.9 microg/mL/hr). CONCLUSIONS: Oxaliplatin was well tolerated in children but has limited activity in children with recurrent CNS embryonal tumors previously treated with platinum compounds.

Adolescent↗
PubMed1997

Characterization of neural cell lines derived from SV40 large T-induced primitive neuroectodermal tumors.

We recently reported intriguing properties of neural tumors generated by retrovirus-mediated transfer of the SV40 large T antigen into fetal rat brain transplants. Histopathologically, these neoplasms displayed characteristic features of primitive neuroectodermal tumors (PNET) and exhibited a striking potential for migration into the host brain. In the present study, four cell lines were derived from these PNETs and characterized. Two lines with an immature phenotype expressed the embryonal form of the neural cell adhesion molecule and nestin. They showed spheroid formation and delicate cell processes. The remaining cell lines had a flat, epitheloid appearance and were immunoreactive for synaptophysin, neurofilament proteins and glial fibrillary acidic protein. These cells constitute valuable tools to study the cellular origin(s) and molecular basis of PNETs, differentiation of neural progenitors and tumor cell migration in the brain.

Animals↗
PubMed1987

Malignant peripheral primitive neuroectodermal tumor of the uterus.

Peripheral primitive neuroectodermal tumor (PPNET) is rare, occurring most often in young adults. Approximately 50 cases have been reported, with only four cases involving the female genital tract. We report the fifth patient. The term "PPNET" should be used only for tumors with neuroectodermal elements exclusively that occur at sites outside the central and sympathetic nervous system. The pathologic differential diagnoses include rhabdomyosarcoma, immature malignant teratoma, small cell carcinoma of the cervix, and ganglioneuroma. Therapy for this tumor has varied, and no effective regimen has been established.

Adolescent↗
PubMed1988

Primitive neuroectodermal tumors of the chest wall.

Primitive neuroectodermal tumor (PNET) is a rare, highly malignant small-cell neoplasm that most often arises from the chest wall or paravertebral region. A patient is described from whom resection, intensive chemotherapy, and bone marrow transplant were unsuccessful. Eleven patients were treated between 1975 and 1985; there was only one long-term survivor (48 months) despite intensive multidisciplinary treatment. The median survival of 49 published cases was 9 months. Conservative resection minimizing disability, radiotherapy, and intensive chemotherapy remain valid options, but use of experimental agents as part of initial therapy seems justified. The role of autologous marrow transplant remains unclear.

Adult↗
PubMed2000

Primary primitive neuroectodermal tumor of the cauda equina.

Primitive neuroectodermal tumors (PNETs) are aggressive neoplasms composed predominantly of undifferentiated cells that show evidence of neural differentiation. Although their classification has been controversial, PNETs are well recognized primary tumors of both central and peripheral nervous systems. PNETs must be distinguished from other round-cell tumors, including Ewing's sarcoma, lymphoma, rhabdomyosarcoma, and small cell carcinoma. Intraspinal PNETs are rare neoplasms that are usually metastatic in origin. We describe the eighth reported primary PNET of the cauda equina that developed in a 52-year-old man with no significant medical history. The tumor was characterized by Homer-Wright rosettes and immunoreactivity for CD99, glial fibrillary acidic protein, neuron-specific enolase S100, and synaptophysin. The anatomic location of primary intrathecal PNETs is important as those arising in the spinal cord develop in the central nervous system, whereas those arising in the cauda equina develop in the peripheral nervous system. The histogenesis of intrathecal PNETs may be multifactorial.

Cauda Equina↗
PubMedDate not supplied

A case of peripheral primitive neuroectodermal tumor of the ovary.

Peripheral primitive neuroectodermal tumor (PNET) belongs to the PNET/Ewing's sarcoma family. PNET is a small round cell tumor of putative neuroectoderm origin and is the second most common sarcoma among children and young adults. It may occur anywhere in the body and within any age group; however, it is most likely to occur in the bone and soft tissues. There have been a small number of case reports of PNET arising in the ovary. We presented a case of PNET arising in the right ovary of an 18-year-old woman. The tumor was metastased to the lymph nodes of the pelvis and para-aorta at surgical staging. We had persecuted Taxol/carboplatin chemotherapy, pelvic cavity radiotherapy, and Vincristine/Actinomycin, Cyclophosphamide/Doxorubicin (VACA). She died after 10 months due to septic shock.

Adolescent↗
PubMed1995

Establishment of a human cell line secreting neuron-specific enolase from a primitive neuroectodermal tumor of the retroperitoneal cavity.

Primitive neuroectodermal tumor (PNET) is one of the small round cell malignancies of presumed neural crest origin for which an effective treatment has not yet been established. In the present study, a human cell line, designated KU-9, was established from a 27-year-old male patient with PNET of the retroperitoneal cavity and has been successfully maintained in nude mice and in culture. On histological examination, the primary tumor was composed of poorly differentiated small round cells arranged in clusters showing a variety of mitotic changes, and contained Homer-Wright rosettes. The histopathological appearance of the KU-9 xenografts was similar to that of the primary tumor. Electron microscopy revealed neurosecretory granules and cytoplasmic processes in the xenograft. No significant amplification of N-myc gene was observed in the KU-9 cells. The KU-9 cells showed chromosome numbers ranging from 56 to 61 with consistent structural abnormalities being add(2)(q31), +add(11)(p11.2), +add(13)(p11.1), and +del(22)(q12). Cultured KU-9 cells grew exponentially with a doubling time of about 50 h and a time-dependent increase in medium levels of neuron-specific enolase (NSE) was noted. Serum levels of NSE in KU-9 tumor-bearing nude mice were significantly elevated and a linear relationship between the serum NSE levels and the tumor NSE content or tumor volume was observed, suggesting that serum levels of NSE may reflect the PNET tumor burden and tumor extent. These results indicate that the KU-9 cell line provides a reproducible model system which could be useful in gaining some insight into the histogenesis and oncogenesis of PNET and in establishing an effective treatment for PNET.

Adult↗
PubMedDate not supplied

Management of children with primitive neuroectodermal tumors of the posterior fossa/medulloblastoma.

Primitive neuroectodermal tumors of the posterior fossa/medulloblastoma (PNET-MB) are the most common malignant primary central nervous system tumors of childhood. Current approaches to therapy for children with PNET-MB are illustrative of both the advances which have been made in management of childhood brain tumors and the areas where increased understanding is needed. With the optimal use of surgery and radiotherapy, the majority of children with PNET-MB can be expected to be alive and free of disease 5 years after diagnosis. Based on various factors, including the age of patient, the extent of the disease at the time of diagnosis and histological parameters, it is possible to stratify patients with PNET-MB into 'risk' groups. It is unclear whether preoperative or postoperative factors are most predictive of outcome. Patients with factors predictive of a higher likelihood of disease relapse seem to benefit from treatment with chemotherapy. The amount of radiotherapy and the type and amount of chemotherapy which is most efficacious in controlling the disease has yet to be determined. Children surviving PNET-MB are at high risk for endocrinologic and neuropsychologic sequelae. Multiple prospective treatment protocols are now underway, attempting to determine which therapy is best at controlling disease without causing severe long-term damage. A multidisciplinary approach is needed for the treatment of children with PNET-MB.

Brain Neoplasms↗