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PubMed2000

[Radiologic diagnosis of malignant tumors of the pelvic bones in children].

An analysis of the data on radiodiagnosis of malignancies of pelvic bones in 50 patients, aged 10-15, is presented. Diagnosis was morphologically confirmed in all the cases: Ewing's sarcoma (41)--82%, primitive neuroectodermal tumor (6)--12% and chondrosarcoma (3)--6%. The leading clinical syndrome was pain in the loin. The significantly most frequent site was the iliac bone. X-ray imaging of tumor site and adjacent areas using standard direct, lateral and oblique projections, ultrasonography, X-ray contrast tomography, radioisotope examination, puncture and open biopsy (when indicated) proved useful.

Adolescent↗
PubMedDate not supplied

Cyclooxygenase-2 (COX-2) overexpression in childhood brain tumors.

The overexpression of COX enzymes has been demonstrated in human neoplasms at various sites, including the colon, gastrointestinal tract, lung, skin and recently in brain tumors. In this study, COX-2 receptor overexpression in primary childhood brain tumors was determined and the distribution pattern of COX-2 receptors was examined. A sensitive, 4-step, alkaline phosphatase conjugated antigen detection technique was used and a specific monoclonal antibody for medulloblastomas/ primitive neuroectodermal tumors (MEDs/PNETs), anaplastic, high-grade astrocytomas (ASTRs) and in glioblastoma multiformes (GMs) was employed. All of the 14 MEDs/PNETs observed demonstrated high levels of immunoreactivity (overexpression), with the highest immunostaining intensity (grades A and B). However, of the 14 subtypes of astrocytic tumors examined, the COX-2 receptor expression level did not even approach those of the MEDs/PNETs levels. However, significant differences were found when comparing low grade pilocytic ASTRs to high grade anaplastic ASTRs and glioblastomas. In two low grade pilocytic ASTRs, the expression level never exceeded 20%, while in high grade glial tumors (6 anaplastic ASTRs and 6 GMs) 30 to 50% of the tumor cells overexpressed COX-2 receptors, documenting an increase in COX-2 receptor overexpression with the increasing grade of the astrocytic tumor. In view of these findings, it would appear likely that COX-2 inhibitors may represent a chemo-preventive tool in treating childhood brain tumors, which are the leading cause of solid tumor cancer death in children under the age of 20.

Brain Neoplasms↗
PubMed2004

C-kit expression and mutational analysis in medulloblastoma.

The proto-oncogene c-kit is a receptor tyrosine kinase recognized to initiate essential signal transduction pathways that transmit biological signals for cellular proliferation, differentiation, and metastasis. Aberrant expression or mutation of c-kit has been shown to be involved in the pathogenesis of many cancers. Studies using imatinib mesylate (STI 571, Gleevec, Novartis, East Hannover, NJ, USA), an inhibitor of the tyrosine kinases brc-abl, c-kit, and PDGFR, have shown significant response in patients with chronic myelogenous leukemia and gastrointestinal stromal tumor. With the aim of identifying additional groups of tumors that may use the stem cell factor/c-kit pathway and, secondarily, may be responsive to imatinib mesylate treatment, we looked at the expression of c-kit in medulloblastoma. Medulloblastoma, a highly invasive primitive neuroectodermal tumor of the cerebellum, is the most common, malignant central nervous system tumor of childhood. Histologic features of medulloblastoma have failed to provide an accurate prediction of the clinical-biological behavior of these tumors. Characterizing the genetic events that play a role in the biology of these tumors may allow for molecular sub-typing and could lead to the development of novel therapeutic strategies. This study evaluated c-kit expression and mutational status in 10 medulloblastoma tumor samples. All 10 medulloblastoma tumors expressed c-kit by reverse transcriptase-polymerase chain reaction and 9 by immunohistochemical analysis. All tumor samples were screened for mutations in exons 9, 11, and 13 of the c-kit gene by direct sequencing. No sequence abnormalities were detected in these exons. These experiments lead us to the conclusion that c-kit activation in medulloblastoma is independent of mutation.

Adolescent↗
PubMed1983

Distribution of immunoreactive S-100 protein in pediatric brain tumors.

The distribution of S-100 proteins was examined in 98 pediatric brain neoplasms with rabbit antiserum to S-100 protein, utilizing the peroxidase-antiperoxidase (PAP) immunohistochemical technique. Positive cytoplasmic immunoreactivity was present in 22 of 24 astrocytomas, both oligodendrogliomas, eight of 13 ependymomas, all 11 choroid plexus tumors, all nine schwannomas, two of six meningiomas, and both meningeal melanomas. Mixed cytoplasmic immunoreactivity was present in both gangliogliomas, all seven craniopharyngiomas, and the only hemangioblastoma. No cytoplasmic immunoreactivity was found in primitive neuroectodermal tumors or germinoma. Nuclear immunoreactivity was present in some cases. Because of the broad spectrum of apparent immunoreactivity with S-100 antiserum, S-100 protein cannot be used as a specific marker of glial or Schwann cell tumors.

Astrocytoma↗
PubMedDate not supplied

Synchronous presentation of an Askin tumor and a plasmacytoma in an adult patient.

Askin tumor, or malignant small round cell tumor of the thoracopulmonary region, is an extremely infrequent entity occurring primarily in children and adolescents. Its histopathologic and cytogenetic features suggest that it belongs to the family of Ewing's sarcoma and primitive neuroectodermal tumors. We report the case of a 43-year-old woman affected by an Askin tumor with bone metastases at diagnosis, presenting synchronously with a plasmacytoma. This is the first reported case of the simultaneous occurrence of an Askin tumor and a malignant hemopathy. The progression of the former and the remission of the plasmacytoma during chemotherapy were remarkable, since Askin tumor treatment shares drugs used for the treatment of plasma cell tumors. Given the infrequent presentation of these diseases in a young adult and the coexistence of two neoplasias characterized by typical chromosomal abnormalities, we consider the possibility of a genetic cancer susceptibility in our patient.

Adult↗
PubMed1998

Myeloablative chemotherapy with autologous bone marrow rescue in young children with recurrent malignant brain tumors.

PURPOSE: This study evaluates the outcome of myeloablative chemotherapy and autologous bone marrow rescue (ABMR) with or without radiotherapy in children younger than 6 years of age with recurrent malignant brain tumors who had not previously been exposed to conventional fractionated external-beam irradiation. PATIENTS AND METHODS: Patients underwent surgery and/or conventional chemotherapy at the time of recurrence to achieve minimal residual disease (two of these patients also underwent local single-fraction gamma-knife radiosurgery). Myeloablative chemotherapy was then administered with carboplatin, thiotepa, and etoposide (16 patients), thiotepa and etoposide (three patients), or thiotepa, etoposide, and carmustine (BCNU; one patient). Autologous bone marrow was re-infused 72 hours after chemotherapy. Twelve patients received external-beam irradiation after recovery from ABMR. RESULTS: Twenty patients with recurrent brain tumors aged 0.7 to 5.9 years (median, 2.9 years) at ABMR were evaluated. Two patients died of toxicity related to myeloablative therapy. Eight patients died of progressive disease. Ten of 20 (50%) patients (primitive neuroectodermal tumor (PNET)/medulloblastoma, three patients; cerebral PNET, three patients; glioblastoma multiforme, two patients; anaplastic astrocytoma, one patient; pineal PNET, one patient) are alive and disease free at a median of 37.9 months (range, 9.7 to 98.2 months) from ABMR (3-year overall survival [OS] rate of 43% +/- 13% and event-free survival [EFS] rate of 47% +/- 14%]. Seven of these 10 patients also received irradiation post-ABMR. CONCLUSION: Myeloablative chemotherapy with ABMR followed by additional external-beam irradiation appears to be an effective retrieval therapy for some young children with recurrent malignant brain tumors.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

High-dose busulfan and thiotepa with autologous bone marrow transplantation in childhood malignant brain tumors: a phase II study.

In order to evaluate the effect of intensive combined chemotherapy in pediatric brain tumors, we designed a phase II study of high-dose busulfan and thiotepa followed by bone marrow transplantation (BMT) in children with measurable recurrent brain tumors. As alkylating agents, busulfan and thiotepa were expected to exhibit a steep dose effect and no overlapping extramedullary toxicity. Moreover, both drugs have an excellent distribution into the central nervous system in humans. Since May 1988, 20 children (median age 6 years) have been treated. Busulfan (150 mg/m2/day x 4) given orally was followed by thiotepa (350 mg/m2/day x 3), given as a 1 h i.v. infusion. Cryopreserved bone marrow was reinfused 48 h after completion of chemotherapy. Tumor response was assessed by computed tomography and magnetic resonance imaging 4 to 6 weeks after BMT. Five partial responses were observed (three of six medulloblastomas, one of five ependymomas, one of two primitive neuroectodermal tumors); two patients with medulloblastoma and one with brain stem tumor achieved an objective response. Ten patients had stable disease and one progressive disease. One patient is not evaluable because of early toxic death. Toxicity was high in terms of aplasia and cutaneous, hepatic and neurological complications. The overall response rate of 26% is encouraging since all patients had disease refractory to all conventional therapies.

Adolescent↗
PubMed1992

Nestin expression in embryonic human neuroepithelium and in human neuroepithelial tumor cells.

Nestin is a recently described member of the intermediate filament (IF) protein family that is especially abundant in neuroepithelial stem cells of the rat. The studies described here examine this class VI IF protein in the normal human developing central nervous system (CNS), human brain tumor-derived cell lines, and tissue samples of human CNS tumors. Human nestin exhibited biochemical and immunochemical properties similar to those of rat nestin. Further, as in the rat, nestin was detected immunohistochemically in several different types of immature human CNS cells, i.e. germinal matrix cells, neuroepithelial cells lining the central canal, radial glia and vascular cells. Nestin appeared in these cells at the earliest gestational age (i.e., 6 weeks) examined here and then it declined in all but the vascular cells at later embryonic stages. Nestin also was detected by immunocytochemistry in 6 of 7 primitive neuroectodermal tumor cell lines and in both of 2 malignant glioma cell lines examined. In these cell lines, nestin co-localized incompletely with bundles of IFs containing other IF proteins (i.e., vimentin, glial filament, neurofilament). Nestin was ubiquitous in a wide variety of brain tumors, but was most prominent in gliomas. The transient expression of nestin in primitive neuroepithelial cells at early stages of human embryogenesis and its abundance in neuroepithelial tumors suggest a role for nestin IFs in cellular events that precede the exit of embryonic CNS stem cells from the cell cycle and the commitment of the progeny of these stem cells to a specific lineage. The subsequent induction of different members of the IF protein family in phenotypically distinct CNS cells (i.e. neurons, glia) and the elimination of nestin from almost all differentiated CNS cells, imply that different classes of IFs subserve functions that are closely linked to the maturational state, as well as the lineage, of CNS cells.

Adolescent↗
PubMed1996

Cellular and molecular pathology of medulloblastoma.

Medulloblastoma is a malignant embryonal tumor predominantly of childhood. It occurs principally in the midline cerebellar region but is prone to invade the meninges and cerebrospinal fluid spaces. It is the principal posterior fossa tumor in children and represents 20% of all brain tumors in this age group. Considerable advances have been made in characterizing the morphologic subtypes, immunophenotypes, and in vitro behavior of cell lines. However, the cell of origin and its relationship to other related primitive neuroectodermal tumors remains uncertain. Although recent advances in the application of proliferation markers and the use of apoptosis in situ labelling have been applied, a prognostically relevant marker applicable to surgical neuropathology remains to be developed. The fundamental molecular pathogenesis of tumor development remains unknown, although recent exciting advances have shown alterations in some members of the PAX family of genes as well as increased expression of neurotrophin receptors. These may prove to be of prognostic significance.

Adult↗
PubMed1997

Primary malignant rhabdoid tumor of the cerebellum.

Malignant rhabdoid tumor (MRT) is a recently described variety of childhood renal neoplasm. MRT arising primarily in the central nervous system (CNS) is still a rather unfamiliar pathological entity and is frequently misdiagnosed as medulloblastoma or primitive neuroectodermal tumor (PNET). We describe a 7-month-old boy who harbored a CNS-MRT that originated within the IV ventricle and invaded the brain stem and the cerebellar hemispheres. After an initial documented good response to chemotherapy the tumor recurred locally 9 months after operation. We discuss clinical and histopathological features distinguishing between PNET/medulloblastoma and MRTs. Current literature on MRT of the CNS is briefly reviewed.

Cerebellar Neoplasms↗
PubMed1997

Cystatin C and transthyretin expression in normal and neoplastic tissues of the human brain and pituitary.

The localization of cystatin C (CC) and transthyretin (TTR) synthesis was studied using Northern blot and immunohistochemical methods. Normal brain tissues from all sites studied contained CC mRNA. Immunoreactive CC was present in the choroid plexus epithelial cells, cerebral and cerebellar neurons, astrocytes, ependymal cells, macrophage-like cells of the arachnoid membrane and in neuroendocrine cells of the anterior pituitary lobe. TTR mRNA and TTR were restricted to the choroid plexus. In primary brain tumors, the transcript for CC was found in all 39 tumors examined, while the protein could only be demonstrated in 3/5 choroid plexus papillomas, 8/8 astrocytomas, 7/23 anaplastic astrocytomas and glioblastomas, 1/6 oligodendrogliomas, 1/1 oligoastrocytoma, 1/4 anaplastic oligodendrogliomas, 3/7 ependymomas, 0/1 anaplastic ependymoma, 0/5 primitive neuroectodermal tumors, 0/1 neuroblastoma, 3/11 meningiomas and 16/16 pituitary adenomas. CC cannot be used as a marker for any specific brain tumor type but the fact that the protein could be demonstrated more frequently in astrocytomas than in their more malignant counterparts suggests that the cellular production and secretion of CC changes with the malignant progression of these tumors. TTR mRNA and TTR were present only in the choroid plexus papillomas, indicating that TTR synthesis is mainly restricted to such brain neoplasms.

Blotting, Northern↗
PubMedDate not supplied

Neonatal brain tumors: CT and MR findings.

Twelve neonatal brain tumors, presenting within 60 days of birth, constituted 3.3% of pediatric brain tumors. Three-fourths were supratentorial. Two-thirds were benign. Forty-two percent were choroid plexus papilloma. Twenty-five percent were teratoma. Eight percent each were hypothalamic glioma, gliosarcoma, medulloblastoma, and primitive neuroectodermal tumor. Clinical symptoms were nonspecific. Signs of herniation were absent in all 12 patients. Forty-two percent of these patients died 1 day to 8 months after diagnosis. Ultrasound, CT, and magnetic resonance have all proved useful for displaying these lesions suitably for surgery.

Brain Neoplasms↗
PubMed2000

Identification of beta-tubulin isoforms as tumor antigens in neuroblastoma.

There is currently substantial interest in the identification of human tumor antigens for diagnosis and immunotherapy of cancer. We have implemented a proteomic approach for the identification of tumor proteins that elicit a humoral response in cancer patients, which we have applied to neuroblastoma. Proteins from neuroblastoma tumors and cell lines were separated by two-dimensional PAGE and transferred to poly(vinylidene difluoride) membranes. Sera from 23 newly diagnosed patients with neuroblastoma, from 12 newly diagnosed children with other solid tumors, and from 13 normal individuals were screened for IgG and IgM autoantibodies against neuroblastoma proteins by means of Western blot analysis. Sera from 11 patients with neuroblastoma and from 1 patient with a primitive neuroectodermal tumor, but none of the other controls exhibited IgG-based reactivity against a protein constellation with an estimated Mr 50,000. NH2-terminal sequence and mass spectrometric analysis identified the major constituents of this constellation as beta-tubulin isoforms I and III. The IgG antibodies were additionally characterized to be of the subclass IgG1. Neuroblastoma patient sera that contained anti-beta-tubulin IgG antibodies also contained IgM antibodies specific against the full-length beta-tubulin molecule and against COOH-terminal beta-tubulin cleavage products. Neuroblastoma patient sera that reacted with beta-tubulin I and III isoforms in neuroblastoma tissues did not react with beta-tubulin I and III isoforms found in normal brain tissue. Our findings indicate the occurrence of beta-tubulin peptides in neuroblastoma, which are immunogenic. The occurrence of immunogenic peptides in neuroblastoma may have utility in diagnosis and in immunotherapy of this aggressive childhood tumor.

Adolescent↗
PubMed1984

Spinal metastases. A rare mode of presentation of brain tumors.

An analysis of more than 18,000 primary central nervous system (CNS) tumors revealed only 18 cases (0.01%) in which dropped spinal metastases had caused the presenting symptoms. This group included 11 males and 7 females in whom there was no history of surgical intervention or irradiation. Primitive neuroectodermal tumors ( PNET , medulloblastoma), comprised the largest group (11 patients) followed by high-grade astrocytomas (anaplastic and glioblastoma) (5 patients). One case each of germinoma and ependymoma were also identified. The clinicopathologic data of these cases, and a brief review of the literature are presented.

Adolescent↗
PubMed1995

The World Health Organization's histologic classification of bone tumors. A commentary on the second edition.

BACKGROUND: The World Health Organization's histologic classification of bone tumors was revised in 1993. METHODS: The first edition was reviewed by an international panel of pathologists from nine countries and modified to incorporate advances made in the twenty years since it appeared. RESULTS: The framework and concept of the classification remain the same (i.e., based on histologic criteria in terms of differentiation shown by the tumor cells via conventional light microscopy supplemented by immunohistochemistry). New entities not described in the first edition include, for example, benign and malignant fibrous histiocytomas, well differentiated osteosarcoma, round-cell osteosarcoma, clear cell chondrosarcoma, primitive neuroectodermal tumor of bone, osteofibrous dysplasia, and giant cell reparative granuloma. CONCLUSION: The revised and expanded classification reflects advances in our knowledge, but is similar in concept and framework to the original version to allow comparisons between data collected in the past and future.

Humans↗
PubMed2006

Efficacy of vincristine and etoposide with escalating cyclophosphamide in poor-prognosis pediatric brain tumors.

The objective of this study was to assess the efficacy of the VETOPEC regimen, a regimen of vincristine and etoposide with escalating doses of cyclophosphamide (CPA), in pediatric patients with high-risk brain tumors. Three consecutive studies by the Australia and New Zealand Children's Cancer Study Group--VETOPEC I, Baby Brain 91, and VETOPEC II--have used a specific chemotherapy regimen of vincristine (VCR), etoposide (VP-16) and escalating CPA in patients with relapsed, refractory, or high-risk solid tumors. Patients in the VETOPEC II cohort were treated with very high dose CPA with peripheral blood stem cell (PBSC) rescue. We analyzed the subset of patients with high-risk brain tumors treated with these intensive VETOPEC-based protocols to assess the response, toxicity, and survival. We also assessed whether the use of very high dose chemotherapy with stem cell rescue improved the response rate or affected toxicity. Seventy-one brain tumor patients were treated with VETOPEC-based protocols. Of the 54 patients evaluable for tumor response, 17 had a complete response (CR) and 20 a partial response (PR) to treatment, which yielded an overall response rate of 69%. The CR + PR was 83% (19/23) for medulloblastomas, 56% (5/9) for primitive neuroectodermal tumors, 55% (6/11) for grade 3 and 4 astrocytomas, and 80% (6/8) for ependymomas. At a median follow-up of 36 months, overall survival for the entire cohort of 71 patients was 32%, with event-free survival of 13%. There were no toxic deaths within the PBSC-supported VETOPEC II cohort, despite higher CPA doses, compared with 7% among the non-PBSC patients. This regimen produces high response rates in a variety of very poor prognosis pediatric brain tumors. The maximum tolerated dose of CPA was not reached. Higher escalation in doses of CPA did not deliver a further improvement in response. With PBSC rescue in the VETOPEC II study, hematologic toxicity was no longer a limiting factor. The response rates observed support further development of this chemotherapy regimen.

Adolescent↗
PubMedDate not supplied

Fine needle aspiration biopsy of a small round cell tumor exhibiting both neural and myogenic differentiation. A case report.

BACKGROUND: Divergent differentiation may not be detected in the limited material available in a fine needle aspiration biopsy (FNAB). CASE: A small round cell malignancy showed neural features ultrastructurally on FNAB, in keeping with primitive neuroectodermal tumor, but desmin and actin positivity on surgical biopsy, suggesting rhabdomyosarcoma. CONCLUSION: Accurate classification of small round cell tumors by FNAB is more likely to occur when both electron microscopy and immunocytochemistry are employed since these tumors may express divergent differentiation.

Adult↗
PubMed1997

Malignancy after retinoblastoma: secondary cancer or recurrence?

The risk of second malignancy after retinoblastoma is reported to be as high as 20% at 10 years after initial diagnosis. This incidence may be an overestimate because of difficulties in distinguishing a second malignancy from recurrent tumor. We encountered a patient with bilateral retinoblastoma who developed a temporal mass 3.5 years after initial treatment for what had first been diagnosed as rhabdomyosarcoma; further study suggested that it was recurrent retinoblastoma manifesting as primitive neuroectodermal tumor (PNET) with multilineage differentiation. Chromosome 13 abnormalities were compatible with either rhabdomyosarcoma or recurrent retinoblastoma. To determine how often second malignancies in retinoblastoma patients may be confused with recurrent primary tumor, we reviewed our experience at Children's Hospital of Pittsburgh. Of 43 retinoblastoma patients seen between 1951 and 1992, presumed second malignancies were documented in four, including the current case. Of the three other second tumors, one had both neural and skeletal muscle differentiation; another was diagnosed as rhabdomyosarcoma unclassifiable as embryonal or alveolar; the last was an osteosarcoma. Only the osteosarcoma was clearly a second neoplasm; two and perhaps three of the other cases may be recurrent retinoblastoma. The distinction between second malignancy and recurrent retinoblastoma may be difficult but is worth determining, because treatment may differ, depending on the correct designation.

Chromosome Banding↗