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PubMed1998

Poorly differentiated synovial sarcoma: immunohistochemical distinction from primitive neuroectodermal tumors and high-grade malignant peripheral nerve sheath tumors.

Synovial sarcoma is a relatively common sarcoma in adults, which in its classic bimorphic form infrequently poses a diagnostic problem. Monomorphic spindled variants, as well as the less common poorly differentiated variants, may be confused with other soft-tissue sarcomas; the poorly differentiated variant (PDSS), in particular, may be histologically indistinguishable from other small, blue, round cell tumors, including primitive neuroectodermal tumors (PNETs). Detection of the synovial sarcoma-associated t(X;18) by either cytogenetic or molecular genetic approaches may be necessary to confirm the diagnosis of synovial sarcoma in difficult cases. We evaluated 10 cases of PDSS from eight patients using a panel of antibodies (including those to intermediate filament proteins, nerve-sheath associated markers, and neuronal and neuroectodermal associated markers) in order to better establish the immunophenotype of this tumor and to help distinguish it from the tumors with which it may be confused, particularly PNETs and high-grade malignant peripheral nerve sheath tumors (MPNSTs). Our results showed PDSS to have significant immunophenotypic overlap with both PNETs and MPNSTs. In most instances these three entities may be differentiated by a panel of antibodies that should include those to both low and high molecular weight cytokeratins, epithelial membrane antigen, type IV collagen, CD99, CD56, and S-100 protein. Our results also suggest that synovial sarcoma may be a tumor showing combined neuroectodermal and nerve sheath differentiation--perhaps because of translocation-associated expression of specific proteins--rather than a carcinosarcoma of soft tissues or a tumor of specialized arthrogenous mesenchyme.

12E7 Antigen↗
PubMed1998

Peripheral primitive neuroectodermal tumors in adults: documentation by molecular analysis.

PURPOSE: The Ewing tumor (ET) family of peripheral primitive neuroectodermal tumors (pPNETs) are primitive small round-cell tumors (SRCTs) of the bone and soft tissue that occur predominantly in children and adolescents. However, pPNETs only rarely enter the differential diagnosis of bone and soft tissue SRCTs in adults. Recently, gene fusions between the EWS gene and different members of the ETS transcription factor family have been shown to occur in virtually all pPNETs and thus constitute a pathognomonic marker for this tumor subclass. The aim of the present study was to document EWS/ETS fusion gene expression in suspected pPNETs of adults as objective evidence for the existence of this tumor family in older patients. PATIENTS AND METHODS: The three contributing molecular diagnostic laboratories retrospectively compiled a cohort of all SRCT cases in which EWS/ETS gene fusions had been shown by molecular analysis. This cohort was surveyed for cases that occurred in patients aged 40 years or older, which were then analyzed for their clinical and pathologic features. RESULTS: Nine patients between 40 and 65 years of age were found to have tumors positive for EWS/ETS gene fusions. Standard histopathologic and clinical features of these cases, other than age, were similar to those of childhood pPNETs. Patients were initiated on appropriate therapy after molecular analysis confirmed the diagnosis of pPNET. CONCLUSION: Identification of an EWS/ETS gene fusion is useful in providing objective evidence of the diagnosis of pPNET in patients over the age of 40 years. This diagnosis should be considered in adults who present with bone and soft tissue SRCTs and appropriate biopsy specimens should be collected for molecular analysis at the time of diagnosis.

Adult↗
PubMed1997

Ewing's sarcoma and primitive neuroectodermal tumor in adults: are they different from Ewing's sarcoma and primitive neuroectodermal tumor in children?

PURPOSE: To determine whether age at diagnosis influences the behavior of Ewing's sarcoma and primitive neuroectodermal tumor (PNET). PATIENTS AND METHODS: We reviewed the clinical features, treatment, and outcome of 59 consecutive patients with Ewing's sarcoma and PNET treated on the Adult Sarcoma Unit at our institution from 1980 to 1995. RESULTS: The 37 male and 22 female patients had a median age of 24 years. Lower limb was the most common primary tumor site. Fifteen patients had nonmetastatic tumor less than 100-mL volume, 27 had nonmetastatic disease greater than 100-mL volume, and 17 had evidence of metastatic disease at presentation. The origin of the primary tumor was soft tissue in 28 cases, bone in 30, and uncertain in one. The Kaplan-Meier estimate of 5-year overall survival (OS) in all patients was 38% and of progression-free survival (PFS), 27%. When patients with metastatic disease at presentation were excluded, these figures increased to 52% and 34%, respectively. Bulk of disease at presentation and response to primary treatment were statistically highly significant predictors of both PFS and OS. Age and tissue of origin of the tumor did not influence outcome. CONCLUSION: The behavior of Ewing's sarcoma and PNET in adults is no different from its behavior in children. We feel the way forward in the treatment of adults with Ewing's sarcoma and PNET is for them to be included in the current multicenter trials of multidisciplinary treatment directed at children.

Adolescent↗
PubMed1984

CNS primitive neuroectodermal tumors of childhood.

Primitive neuroectodermal tumors ( PNET ) of the central nervous system in children are rare, highly malignant, cystic, and sometimes calcific, and hemorrhagic tumors sharply demarcated from adjacent brain. Microscopically they consist of small predominantly undifferentiated dark cells with neuronal, glial, and mesenchymal elements. We have recently diagnosed and treated five children with PNET . We will review their case histories as well as summarize the previous 133 reported cases with reference to presenting complaints, tumor location, neurodiagnostic studies, and the retrospective results of four treatment programs: 1) surgery alone; 2) surgery and radiation therapy; 3) surgery, radiation therapy, and chemotherapy at time of recurrence; and 4) surgery, radiation therapy, and chemotherapy at onset.

Brain Neoplasms↗
PubMed1996

Glial differentiation predicts poor clinical outcome in primitive neuroectodermal brain tumors.

Primitive neuroectodermal tumors (PNETs) of the central nervous system, including medulloblastomas (PNET/MB), are the most common malignant brain tumor of childhood. These tumors often express proteins characteristic of glial differentiation (glial fibrillary acidic protein, GFAP), neuronal differentiation (neurofilament proteins, NFPs), and/or photoreceptor differentiation (retinal-S antigen). To identify biological factors of prognostic significance in PNETs, the expression of glial, neuronal, or photoreceptor antigens was evaluated in the tumor specimens of 86 patients with PNETs by immunohistochemistry after microwave antigen enhancement. Patterns of differentiation were then compared with patient relapse-free survival. Multivariate analysis of PNET immunohistochemistry and clinical variables indicated GFAP expression conferred a 6.7-fold greater risk of relapse than tumors that did not express GFAP or NFPs. Increased risk of relapse was directly related to the amount of GFAP expression. Tumors exhibiting clumps or sheets of GFAP-staining cells were associated with a 3.0-fold increased risk of relapse compared with tumors that did not express GFAP, irrespective of immunohistochemical evidence of other differentiation, while scattered GFAP staining was not associated with increased risk of relapse. These findings indicate that expression of GFAP in PNETs has prognostic power comparable with the most significant clinical factors currently used to predict clinical outcome.

Adolescent↗
PubMed1991

MIC2 is a specific marker for Ewing's sarcoma and peripheral primitive neuroectodermal tumors. Evidence for a common histogenesis of Ewing's sarcoma and peripheral primitive neuroectodermal tumors from MIC2 expression and specific chromosome aberration.

This study reports on the specific expression of the MIC2 gene, a pseudoautosomal gene located on the short arms of the X and Y chromosomes, on Ewing's sarcoma (ES) and peripheral primitive neuroectodermal tumor (pPNET) cells. The gene product, a cell membrane protein, is recognized by the newly established monoclonal antibody (MoAb) HBA-71 and the previously described MoAb 12E7 and RFB-1. Furthermore, the reaction pattern of the MIC2 antibodies, especially HBA-71, with normal tissues and a great number of benign and malignant tumors (70 different tumors, 199 tumor samples), as well as the correlation between the specific chromosomal aberrations, i.e., the t(11;22) and the del(22) and the expression of this antigen, are demonstrated. Both ES and pPNET cells express the MIC2 gene in very high amounts, which represents a highly selective and almost unique feature of these cells, making an assignment of these tumors in one entity even more likely. The MIC2 antibodies are of great value for clinical and research purposes.

12E7 Antigen↗
PubMed1999

Pineal and nonpineal supratentorial primitive neuroectodermal tumors.

Pineal region supratentorial primitive neuroectodermal tumors (SPNETs; pineoblastomas) and nonpineal SPNETs are rare tumors that historically have carried a very poor prognosis. With multimodality therapy, including maximal surgical resection, craniospinal radiation therapy and chemotherapy, the survival for patients with pineal PNETs has significantly improved. Chemotherapy alone, at least in conventional doses, appears to be insufficient treatment for younger children with pineoblastomas, in whom there is almost universal rapid tumor progression and death. Survival of patients with nonpineal SPNETs remains in the order of 30-35% despite multimodality therapy. Unlike those with pineal SPNETs, a significant percentage of infants with nonpineal SPNETs who undergo gross total surgical resection followed by chemotherapy will be long-term survivors. This article gives an overview of the natural history, prognostic factors and treatment of both pineal and nonpineal SPNETs.

Child, Preschool↗
PubMed1999

Neurotrophins and Trk receptors in primitive neuroectodermal tumor cell lines.

OBJECTIVE: Primitive neuroectodermal tumors (PNETs) are thought to be derived from early central nervous system precursors. Therefore, we hypothesized that the neurotrophins (nerve growth factor, brain-derived neurotrophic factor, and neurotrophin-3) and their receptors (TrkA, TrkB, and TrkC), which are involved in the proliferation, differentiation, and survival of neuronal cells, might be important in regulating tumor growth. METHODS: Using ribonucleic acid (RNA) blotting and reverse transcription-polymerase chain reaction analysis, we investigated the expression of these ligands and their receptors in six PNET cell lines (Daoy, PFSK, D283 Med, UW288-1, CHP707m, and D341 Med). Neurotrophin protein levels were measured using enzyme-linked immunosorbent assay procedures. Receptor function was demonstrated by autophosphorylation. Induction of c-Fos expression and effects on cell proliferation were assessed after the addition of exogenous neurotrophin. RESULTS: Three cell lines expressed messenger RNA for all neurotrophins, whereas the other three expressed two of the three neurotrophins. Neurotrophin protein levels were low. All cell lines expressed trkA messenger RNA. Five expressed the amino terminus of trkB, but three of these did not express the carboxyl terminus. All cell lines contained trkC messenger RNA, but the receptor was truncated in two cell lines. No cell line contained message for a receptor containing an insertion in the tyrosine kinase domain. The addition of neurotrophin to PNET cells resulted in phosphorylation of a protein that was immunoprecipitated with an anti-pan-Trk antibody. c-Fos expression and cell growth were increased by preincubation with neurotrophins, but only in the cell lines expressing the relevant full-length receptors. CONCLUSION: The expression of neurotrophins and neurotrophin receptors by PNET cell lines is variable. The presence of activated Trk receptors in these cell lines may be required for rapid growth, via an autocrine loop mechanism. This will require further investigation.

Brain Neoplasms↗
PubMed1983

Primitive neuroectodermal tumors of the central nervous system.

Primitive neuroectodermal tumors are morphologically similar malignant tumors arising in intracranial and peripheral sites of the nervous system, showing varying degrees of cellular differentiation with a tendency to disseminate along cerebrospinal fluid pathways. They occur primarily in children and young adults. Under the designation primitive neuroectodermal tumors are included medulloblastomas and tumors that may differentiate in other directions, such as medulloepithelioma, neuroblastoma, polar spongioblastoma, pineoblastoma, ependymoblastoma, retinoblastoma, and olfactory neuroblastoma. From a practical, histologic point of view, these tumors are often indistinguishable from one another and are best thought of as primitive neuroectodermal tumors with or without differentiating features.

Animals↗
PubMedDate not supplied

Current diagnostic and therapeutic management of CNS metastasis in childhood primitive neuroectodermal tumors and ependymomas.

Metastatic disease is a major problem in the management of the most frequent childhood brain tumors, in ependymoma and primitive neuroectodermal tumors (PNET). Today, contrast enhanced craniospinal MRI and careful analysis of craniospinal fluid are a prerequisite for correct staging of both tumors and imply therapeutic consequences. So far metastatic spread of medulloblastoma and some ependymomas is prevented by conventional chemotherapy and radiotherapy. However, some forms of diffuse metastatic dissemination in medulloblastoma are resistant to conventional therapeutic regimens and require new experimental strategies.

Brain Neoplasms↗
PubMed1995

Primitive neuroectodermal tumor of maxilla in an adult.

Primitive neuroectodermal tumor is primarily a central nervous system tumor. These tumors are generally manifest in infancy or early childhood. The following article reports a rare case of primitive neuroectodermal tumor in posterior maxilla in an adult. Treatment for primitive neuroectodermal tumor in extracranial sites in adults is not clearly defined in the literature. This case was treated by combined chemotherapy followed by radiotherapy, which failed to cause regression of the lesion.

Adult↗
PubMed1995

Peripheral primitive neuroectodermal tumors of the head and neck.

OBJECTIVE: Primitive neuroectodermal tumor is a malignant small round cell tumor of neuroectodermal origin. The occurrence of these tumors in the head and neck is rare. Our objective is to document the frequency of presentation, methods of diagnosis, and forms of treatment used to combat primitive neuroectodermal tumors in the head and neck. DESIGN: Retrospective chart review. RESULTS: The most common location for primitive neuroectodermal tumors in our series was the thoracopulmonary region (46%); the next most common location was the head and neck (42%). Metastatic disease was present in 31% of patients at the time of diagnosis. Cytogenic analysis was found to be helpful in confirming the diagnosis of primitive neuroectodermal tumor. Therapy for primitive neuroectodermal tumors included surgery, chemotherapy, and radiation therapy. Survival statistics were poor, with 65% of the patients alive at 2 years' follow-up. CONCLUSIONS: Primitive neuroectodermal tumor is an aggressive malignant small round cell tumor that may present in the head and neck. Long-term survival for patients with primitive neuroectodermal tumor is still poor; however, the use of improved chemotherapeutic agents combined with aggressive surgical control of primary disease and, in some cases, radiation therapy should lead to improved long-term survival.

Adolescent↗
PubMed1990

Reduction to homozygosity and gene amplification in central nervous system primitive neuroectodermal tumors of childhood.

The loss of genetic material from specific chromosomal locations has been identified for a number of pediatric tumors. This loss has been taken as evidence for the importance of tumor suppressor genes at these loci in the genesis of these tumors. One of these pediatric tumors, the primitive neuroectodermal tumor of the central nervous system, has not been well studied. In this report, an analysis of primitive neuroectodermal tumors for allelic deletions on chromosomes 1p, 7q, 10, 11p, 13q, and 17p has been performed. One of ten tumors was found to have increased copies of c-myc. Three different patients were found to reduce to homozygosity at one of three different locations. Significantly, however, three of nine informative patients showed a reduction to homozygosity on chromosome 17p. Thus, primitive neuroectodermal tumor is one of a growing number of tumor types in which deletions in the short arm of chromosome 17 might be important in oncogenesis.

Brain Neoplasms↗
PubMed1995

Growth-inhibiting effect of intratumoral recombinant human tumor necrosis factor on an experimental model of primitive neuroectodermal tumor.

The effect of intratumoral administration of recombinant human tumor necrosis factor on an experimental model of primitive neuroectodermal neoplasia was studied. A clear inhibition of tumor growth was achieved by immunotherapy that consisted in intralesion injections of 100 micrograms of tumor necrosis factor daily, the first three days of each week, for a period of four weeks. At this time, tumor size was 2.21 +/- 0.66 cm2 (mean +/- standard deviation) in the treated group, versus 7.62 +/- 0.43 cm2 in the control group. These data support previous studies on the influence of tumor necrosis factor on the development of ethyl-nitrosourea-induced tumors, and suggest the potential usefulness of this cytokine in human primitive neuroectodermal neoplasms.

Animals↗
PubMed1994

Experimental production of primitive neuroectodermal tumors and its relevance to human neuro-oncology.

The origin and nature of central nervous system tumors primarily composed of primitive neuroepithelial cells have intrigued neuropathologists since 1925, when the prototype tumor in this group, the medulloblastoma, was defined as a specific type by Bailey and Cushing. Theories regarding this group of tumors have been widely divergent, ranging from classification as sarcomas, neuroblastomas, spongioblastomas, ie, poorly differentiated gliomas (including astrocytic, oligodendroglial, and ependymal), to primitive tumors with a capacity for multidirectional differentiation. Studies of both human and experimental primitive neuroectodermal tumors have yielded considerable information about biological features, although controversies remain regarding interpretation of the findings. Moreover, many investigators remain fixed upon the notion that discovery of the "cell of origin" of these tumors will somehow enhance understanding of their nature. Rationale for relevance of this view is examined against the current state of knowledge regarding carcinogenesis as a whole and studies of human and experimental primitive neuroectodermal tumors in particular, and it is concluded that the time has come to discard the archaic concept of cell of origin and devote resources to investigations of the phenotypic character of the tumor and its relationship to prognosis and treatment.

Animals↗
PubMed1998

[Primitive neuroectodermal tumors: difficult tumors versus modern oncology].

INTRODUCTION: Primitive peripheral neuroectodermal tumours (PNET) are rare masses and form part of the group of round small cell tumours which include a wide range of highly aggressive neoplasias such as Ewing's sarcoma, neuroblastoma, lymphoma and rhabdomyosarcoma. PNET present the same cell line as the tumours presented by F. Askin in 1979, both located in the thoracic-pulmonary region. MATERIAL AND METHODS: Of the last 26 thoracic neuroblastomas and 11 mediastinal-thoracic sarcomas treated at our centre, we observed 5 PNET in children with a mean age of 12 years (range: 9-14 years). These patients presented a thoracic mass infiltrating sternum, clavicle, supraspinal muscle or, in two cases, a left lateral or paravertebral intrathoracic mass. The time elapsed between clinical observation and diagnosis was 6 weeks. Diagnosis was established by chest X-Ray, CT, bone scintigraphy, immunocytochemistry and cytology. Aggressive local treatment associated with stage IV SIOP chemotherapy for rhabdomyosarcoma was applied in all cases to prevent metastasis. RESULTS: Of the five PNET treated, one 16-year-old patient died (4 y 5 m post-diagnosis) from bone marrow infiltration which had evolved badly from the beginning. The remaining patients are disease-free. One patient who did not undergo surgery relapsed 1 year and the half after completing chemotherapy. He then underwent resection of the cranial portion of the sternum and substitution with iliac graft from the tissue bank. CONCLUSION: PNET manifest clearly some of the characteristics of current paediatric oncology. These tumours are easily misdiagnosed and at present may be differentiated by new diagnostic methods (immunohistochemistry, cytogenetics, hybridomas, molecular genetics), with the aim of selecting the most adequate treatment and consequently improving the prognosis of these aggressive embryonary tumours.

Adolescent↗