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PubMed1996

Coexpression of platelet-derived growth factor alpha and beta receptors on medulloblastomas and other primitive neuroectodermal tumors is consistent with an immature stem cell and neuronal derivation.

Medulloblastomas and related childhood primitive neuroectodermal tumors (PNET) are currently thought to originate from a multipotent stem cell that can give rise to a variety of different tumor types, representing different lines of differentiation and stages of maturation of the original stem cell. The proliferation and differentiation of different cell types in the central nervous system are influenced by growth factors, such as platelet-derived growth factor (PDGF). In this study, we investigated the expression of the two types of PDGF receptors, alpha and beta, on 14 cases of PNET by immunohistochemistry and in situ hybridization. To characterize the tumor cells according to their differentiation and maturation, we performed immunohistochemistry with Ab against several members of the intermediate filament family, such as neurofilament, glial fibrillary acidic protein, vimentin, and the embryonal marker nestin. For the cerebral PNET, we found that the phenotype of multidirectional differentiation (with coexpression of neurofilament, glial fibrillary acidic protein, vimentin, and in some cases nestin) was associated with the expression of both PDGF alpha and beta receptors on the tumor cells. Medulloblastomas (i.e., cerebellar PNET), however, often showed the phenotype of partially committed neuron-like precursor cells, and this was associated with the predominant expression of PDGF alpha receptors on the tumor cells. Our findings show that the PDGF alpha receptor, previously known to play a role in the normal development of cells of the glial lineage, either exclusively or in combination with the PDGF beta receptor, is expressed on tumor cells of neuronal derivation. This "aberrant" expression of PDGF alpha receptors on PNET may reflect a feature of the malignant phenotype of these tumors. Further studies are needed to study the biologic effects of PDGF-A and its receptor in PNET.

Brain Neoplasms↗
PubMed1999

Peripheral-type primitive neuroectodermal tumor arising in the tentorium. Case report.

The authors report the case of a peripheral primitive neuroectodermal tumor (PNET) arising in the tentorium in a 5-year-old boy who presented with frequent vomiting and mild palsy of the left abducent nerve. Following complete surgical excision of the tumor via a transpetrosal approach, the patient has thus far been disease free for 7 years. The tumor tissue was composed of small cells with uniform round nuclei and minimal identifiable cytoplasm. Homer-Wright rosettes were frequently observed. Immunohistochemical studies demonstrated a positive reaction to HBA-71, which recognizes the cell surface glycoprotein p30/32, a product of the MIC2 gene. Both the clinical and immunohistochemical characteristics of this tumor are consistent with a diagnosis of peripheral PNET, which is genetically distinct from the more common intracranial PNET.

12E7 Antigen↗
PubMed1985

Melanocytic neuroectodermal tumor of the foot. Report of a case with multicentric origin.

This report describes a case of a two-year-old boy who had a tumor of the right fifth metatarsal. Biopsy revealed an undifferentiated, "small, round cell tumor" initially diagnosed as Ewing's sarcoma. He was treated with intensive chemotherapy, followed by amputation of the right foot when no response was observed. The histology of the amputated specimen was typical of melanocytic neuroectodermal tumor, a diagnosis confirmed by electron microscopy. Apart from documenting origin in a heretofore unrecorded site, this case illustrates the difficulties that arise in making a diagnosis and estimating prognosis of melanocytic neuroectodermal tumor, and provides evidence in favor of the multicentric origin of this uncommon disease.

Bone Neoplasms↗
PubMed2002

Role of radiotherapy in the treatment of supratentorial primitive neuroectodermal tumors in childhood: results of the prospective German brain tumor trials HIT 88/89 and 91.

PURPOSE: To evaluate the outcome of children with supratentorial primitive neuroectodermal tumors after surgery, irradiation, and chemotherapy and to identify factors predictive for survival. PATIENTS AND METHODS: Sixty-three children in the prospective trials HIT 88/89 and HIT 91 were eligible. Complete resection was performed in 21 patients. Patients were randomized for preirradiation chemotherapy, consisting of two cycles of ifosfamide, etoposide, methotrexate, cisplatin, and cytarabine (n = 40), or chemotherapy after irradiation, consisting of eight cycles with cisplatin, vincristine, and lomustine (n = 23). Irradiation volume was recommended to encompass the neuraxis with 35.2-Gy total dose followed by a boost (20.0 Gy) to the primary tumor site (n = 54). Seven patients were irradiated to the tumor region only with a total dose of 54.0 Gy. RESULTS: Overall survival at 3 years was 48.4%. Progression occurred in 38 children, with local recurrences in 27 patients. The only significant prognostic factor was dose and volume of radiotherapy (progression-free survival after 3 years was 49.3% with correct treatment compared with 6.7% for 15 children with major violations of radiotherapy). Ten early progressions occurred during adjuvant therapy (eight before and two during radiotherapy), nine of them treated with preirradiation chemotherapy. There was a positive trend in outcome for nonmetastatic and pineal tumors. CONCLUSION: Significant predictive factors were dose and volume of radiotherapy. Volume of irradiation should encompass the whole CNS with additional boost to the tumor region. Local doses of at least 54 Gy and a craniospinal dose of 35 Gy are necessary. Preirradiation chemotherapy seems to increase risk of early progression.

Adolescent↗
PubMed2000

Molecular cytogenetic analysis of medulloblastomas and supratentorial primitive neuroectodermal tumors by using conventional banding, comparative genomic hybridization, and spectral karyotyping.

OBJECT: Medulloblastomas and related primitive neuroectodermal tumors (PNETs) of the central nervous system are malignant, invasive embryonal tumors with predominantly neuronal differentiation that comprise 20% of pediatric brain tumors. Cytogenetic analysis has shown that alterations in chromosome 17, particularly the loss of 17p and the formation of isochromosome 17q, as well as the gain of chromosome 7 are the most common changes among this group of tumors. Comparative genomic hybridization (CGH) studies have largely confirmed these cytogenetic findings and have also identified novel regions of gain, loss, and amplification. The advent of more sophisticated multicolored fluorescence in situ hybridization (FISH) procedures such as spectral karyotyping (SKY) now permits complete recognition of all aberrations including extremely complex rearrangements. The authors report a retrospective analysis of 19 medulloblastoma and five PNET cases studied using combinations of classic banding analysis, FISH, CGH, and SKY to examine comprehensively the chromosomal aberrations present in this tumor group and to attempt to identify common structural rearrangement(s). METHODS: The CGH data demonstrate gains of chromosomes 17q and 7 in 60% of the tumors studied, which confirms data reported in the current literature. However, the authors have also combined the results of all three molecular cytogenetic assays (Giemsa banding, CGH, and SKY) to reveal the frequency of chromosomal rearrangement (gained, lost, or involved in structural rearrangement). CONCLUSIONS: The combined results indicate that chromosomes 7 and 17 are the most frequently rearranged chromosomes (10.1% and 8.9%, respectively, in all rearrangements detected). Furthermore, chromosomes 3 (7.8%), 14 (7%), 10 (6.7%), and 22 (6.5%) were also found to be frequently rearranged, followed by chromosomes 6 (6.5%), 13 (6.2%), and 18 (6.2%). Eight (33%) of 24 tumors exhibited high-level gains or gene amplification. Amplification of MYCN was identified in four tumors, whereas amplification of MYCC was identified in one tumor. One tumor exhibited a high-level gain of chromosome 9p. Additionally, desmoplastic medulloblastomas and large-cell medulloblastomas exhibited higher karyotype heterogeneity, amplification, and aneusomy than classic medulloblastomas.

Brain Neoplasms↗
PubMed1994

Expression of nerve growth factor receptor by human primitive neuroectodermal tumors.

The expression of low-affinity nerve growth factor receptor (NGF-R) by primitive neuroectodermal tumors (PNETs) was analyzed in vivo and in vitro to investigate the relationship between NGF-R expression and cellular differentiation. NGF-R was expressed in one medulloblastoma cell line and two neuroblastoma cell lines. When these cells were induced to differentiate by treatment with dibutyryl cyclic adenosine monophosphate, NGF-R was overexpressed and there was increased expression of neurofilament proteins. Immunohistochemistry investigation of tumor tissues demonstrated that NGF-R was expressed by a subset of PNETs with a neuronal phenotype marked by neurofilament protein expression, but not by gliomas and PNETs without a neuronal phenotype. Growth inhibition assay demonstrated that NGF inhibited the growth of cells expressing NGF-R. These results indicate that NGF-R expression is a useful marker of neuronal differentiation by PNETs.

Blotting, Western↗
PubMed2000

Ewing's sarcoma/primitive neuroectodermal tumor of the ureter: a case report and review of the literature.

Extraosseous Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) is a rare soft tissue tumor of childhood usually found in the extremities. The authors present the case of a 17-year-old girl who presented with right flank pain and hematuria and during operation was found to have a right ureteral mass. The histopathologic, immunohistochemical, ultrastructural, and cytogenetic characteristics of the excised mass were consistent with extraosseous ES/PNET. This is the first known reported case of extraosseous ES/ PNET of the ureter. The pathologic features and clinical management of this case, as well as a review of the literature, are presented.

Adolescent↗
PubMed2002

Primary intraspinal primitive neuroectodermal tumor: case report of a tumor arising from the sacral spinal nerve root and review of the literature.

Primary spinal primitive neuroectodermal tumor (PNET) is a rare condition, 18 cases of which have been reported in the literature. In general, this tumor is treated with surgery followed by radiotherapy and chemotherapy, but prognosis is still poor. An 18-year-old female patient with an intradural, extramedullary mass at L3-L5 levels is presented in this report. This is the first female patient with primary spinal PNET at lumbar region, second patient with spinal nerve root origin, and third one with intradural, extramedullary localization ever reported in the literature. After surgery, she was treated with craniospinal radiotherapy and four cycles of combination chemotherapy regimen consisting of vincristine, cyclophosphamide, doxorubicin alternated with ifosfamide, and VP-16. Currently, she is asymptomatic and alive at 25 months. The histopathologic, radiologic, and clinical findings of the patient are presented and relevant literature is reviewed.

Adolescent↗
PubMed1999

Medulloblastoma and supratentorial primitive neuroectodermal tumors: an institutional experience.

BACKGROUND: To the authors' knowledge there are relatively few data concerning supratentorial primitive neuroectodermal tumors (PNET). The authors retrospectively reviewed all cases of PNET of the brain treated at the study institution to determine whether there was a difference in presentation, overall survival, and recurrence-free survival with regard to tumor location (supratentorium vs. posterior fossa). METHODS: Between 1977-1996 33 patients with PNET were diagnosed and treated at 1 radiotherapy center. The median age of the patients was 9 years. The location of the tumor was in the posterior fossa in 25 patients and the supratentorium in 8 patients. The tumor had spread to the neuraxis in six patients; four patients with disseminated neuraxis disease had a supratentorial PNET and two had a posterior fossa PNET. All but three patients received craniospinal irradiation. The primary tumor received > or = 5000 centigray in 27 patients and chemotherapy was employed in 26 patients. The median follow-up was 60 months. RESULTS: The 5-year overall and recurrence-free survival rates for all patients were 77.2% and 79.6%, respectively. The 5-year overall survival rates were 86.3% for patients with medulloblastoma (posterior fossa PNET) and 46.9% for patients with supratentorial PNET (P = 0.01, log rank test). For overall survival, prognostic factors included radiotherapy dose to the primary site, metastases (M) status, and location of the primary tumor. The 5-year recurrence free survival rates were 89.8% for patients with medulloblastoma and 46.9% for patients with supratentorial PNET (P = 0.003, log rank test). For recurrence free survival, prognostic factors included M status and primary tumor site location; radiation dose to the primary tumor site and patient gender were of borderline significance. In the ten patients with inadequate posterior fossa boost fields judged by Children's Cancer Group criteria, there were two failures, both of which were in the original tumor bed. CONCLUSIONS: Supratentorial PNET has a worse overall survival and recurrence free survival than medulloblastoma. There is a suggestion that radiotherapy boosts in medulloblastoma may not need to encompass the entire posterior fossa because posterior fossa failures primarily are in the tumor bed. Larger studies with longer follow-up are needed to determine whether craniospinal irradiation followed by a boost to the tumor bed is adequate for medulloblastoma patients.

Adolescent↗
PubMedDate not supplied

Primitive neuroectodermal tumor of the kidney. Report of a case initially diagnosed by fine needle aspiration cytology.

BACKGROUND: Primitive neuroectodermal tumor (PNET) is a malignant small round cell tumor that exhibits neuroepithelial differentiation, most often presenting as a bone or soft tissue mass in the trunk or axial skeleton in adolescents and young adults. Isolated cases of PNET have been observed at visceral sites, such as the ovary, testis, uterus, bladder and pancreas. We present a case of PNET in the kidney initially diagnosed by fine needle aspiration (FNA). CASE: A 21-year-old woman presented with microhematuria. Urine cytology was negative for malignant cells. Physical examination was without abnormal findings. Computerized tomography revealed a partially cystic tumor in the left kidney. FNA showed monotonous-appearing small round tumor cells with occasional rosette formation. The differential diagnoses include other primitive small round cell tumors. The tumor cells were immunoreactive for neuron specific enolase and O13 (CD99). A cytologic diagnosis of PNET was suggested and subsequently confirmed on histopathology. CONCLUSION: To our knowledge, this is the first description of PNET of the kidney initially diagnosed by FNA. This nerve tumor must be included in the differential diagnosis of small cell malignant tumors of the kidney and adjacent organs.

12E7 Antigen↗
PubMed2000

Soft tissue Ewing sarcoma--peripheral primitive neuroectodermal tumor with atypical clear cell pattern shows a new type of EWS-FEV fusion transcript.

This study describes a new case of Ewing sarcoma (ES)-peripheral primitive neuroectodermal tumor (pPNET) with unusual phenotype and fusion gene structure. The tumor located in the inguinal area of a 15-year-old boy showed a highly aggressive behavior with hematogenous metastases after intensive chemotherapy and bone marrow transplant, causing death 28 months after diagnosis. The tumor displayed a clear cell pattern, and several neuroectodermal markers proved positive both in the original tumor and in xenografts. This neuroectodermal character was confirmed by electron microscopy. Moreover, cytogenetically the tumor has an unusual chromosomal rearrangement, t(2;22)(q13;q22,t(3;18)(p21;q23); representing a new EWS-FEV fusion type in which exon 7 of EWS gene is fused with exon 2 of FEV gene. This is the third published study of an ES-pPNET showing EWS-FEV fusion described, but it is the first study of a tumor with the aforementioned fusion points. These findings support the genetic and morphologic heterogeneity existing within the group of ES-pPNET tumors.

Adolescent↗
PubMed1996

Renal primitive neuroectodermal tumor: an immunohistochemical and cytogenetic analysis.

The cytogenetic and morphologic characteristics of a case with a primitive neuroectodermal tumor (PNET) arising from the left kidney in a 22 year old man are presented. The patient was detected as having a left renal mass with a tumor embolus in the inferior vena cava and multiple pulmonary metastases. A radical nephrectomy with tumor embolectomy of the inferior vena cava, along with a resection of the pulmonary nodules were performed. Histologic examination revealed a dense proliferation of small round cells with many Homer-Wright type rosettes and perivascular pseudorosettes. Immunohistochemically, the tumor cells stained strongly positive for HBA71(p30/32MIC2), a surface glycoprotein specific to PNET and Ewing's sarcoma. In addition, the tumor cells expressed several neural markers (neuron specific enolase, neurofilament, synaptophysin, and Leu-7) and vimentin, while the epithelial, muscular, and lymphocytic markers were negative in the tumor cells. Cytogenetic analysis of cultured tumor cells showed a reciprocal translocation t(11;22)(q24;q12) that is considered to be specific to PNET and Ewing's sarcoma. In conclusion, this case suggested that a karyotyping analysis is a useful diagnostic tool for renal PNET, and it may therefore be utilized to help distinguish between difficult cases of small round cell tumors and Wilms' tumor of the kidney.

Adult↗
PubMed1990

Congenital cerebral primitive neuroectodermal tumor with astrocytic differentiation and extracranial metastases.

A cerebral primitive neuroectodermal tumor with astrocytic differentiation and extracranial metastases in a 28-day-old infant is reported. The infant presented with a progressively enlarged head, cutaneous lesions in the neck, and enlarged cervical lymph nodes. A computed tomography brain scan demonstrated a giant thalamic tumor with subarachnoid dissemination and hydrocephalus. Biopsy material from the cervical lesions showed a picture of glioma with anaplastic astrocytes. The patient received a ventriculoperitoneal shunt operation and palliative chemotherapy, but died at 3 months of age. Autopsy was performed. Histological studies, which included immunohistochemical stains of the thalamic tumor, showed small, round, primitive, neoplastic cells with focal astrocytic differentiation.

Astrocytes↗
PubMed1989

Multiple neuroectodermal tumors arising in a mature cystic teratoma of the ovary.

Benign cystic teratomas are common, comprising 11-20% of all ovarian tumors. Neural elements can be identified in 38% of teratomas, but the development of a malignant neural neoplasm in an ovarian tumor of this type is rare. Multiple neuroectodermal tumor foci have not been previously described in association with a mature cystic teratoma of the ovary.

Adult↗
PubMed1995

Transplantation of congenital primitive neuroectodermal tumor of fetus to the uterus of mother: application of biotin-labeled chromosome-specific probes.

We report a 38-year-old gravida 3, para 3, white female with an unremarkable history and normal amniocentesis, who delivered a male infant with a large pedunculated and ulcerated tumor by vaginal delivery. A portion of the tumor was sheared and expelled with the normal placenta at the time of delivery. The biopsy of the infant mass and the expelled tissue showed histologic features of a small round cell tumor with immunohistochemical features of a primitive neuroectodermal tumor (PNET). The infant eventually died at the age of 4 weeks as a result of extensive dissemination of tumor. The mother had postpartum bleeding, and fractional dilation and curettage procedures at 6 weeks and 4 months after delivery revealed tumor similar to that of the infant. The mother underwent radical hysterectomy and bilateral salpingo-oophorectomy, which revealed a neoplasm at the junction of the lower uterine segment and cervix. Fluorescent in situ hybridization (FISH) study of both the infant's tumor and the mother's uterine tumor showed positivity for the Y chromosome by using a classical alpha-satellite Y chromosome-specific probe. These findings support the hypothesis that the tumor was transferred from the fetus to the mother.

Journal Article↗
PubMed1989

Monoclonal antibody MB2: a potential marker for Ewing's sarcoma and primitive neuroectodermal tumor.

The small round-cell tumors of childhood present difficulties in diagnosis when differentiation is not apparent. Immunohistochemistry is helpful; however, the only antigen consistently detected in Ewing's sarcoma is vimentin, which may also be detected in the other types of small-cell neoplasms. The monoclonal antibody (MAb) MB2 is marketed as a B-lymphocyte marker that can be used on paraffin-embedded tissue. To determine its specificity, we performed immunohistochemical staining on pediatric tumors with MB2. These included 55 cases of small round-cell tumors (lymphomas, Ewing's sarcoma, peripheral primitive neuroectodermal tumors [PNET], neuroblastomas, rhabdomyosarcomas, and nephroblastomas). MB2 positivity was detected in all B-cell lymphomas and in seven of nine cases of Ewing's sarcoma and three PNET. In neuroblastomas only differentiating ganglion cells were positive. In rhabdomyosarcomas only large rhabdomyoblasts were positive. Blastema of nephroblastomas was negative. Thus, in cases of poorly differentiated small round-cell tumors, MB2 was positive in all B-cell lymphomas, most Ewing's sarcomas and all cases of PNET. Lymphomas were distinguished by staining for leukocyte-common antigen and PNET by neuron-specific enolase. Therefore, the addition of MB2 to a discrete panel of antibodies may prove useful in the diagnosis of Ewing's sarcoma and PNET.

Adolescent↗
PubMed1998

Peripheral Primitive Neuroectodermal Tumor (Peripheral Neuroepithelioma) in a Dog.

A peripherally located primitive neuroectodermal tumor (peripheral PNET) originating in subcutaneous tissues was observed in an adult Beagle. The highly aggressive tumor spread rapidly and metastasized to various organs. The neoplasm was diagnosed as a peripheral PNET on the basis of morphologic and immunohistochemical characteristics such as small round tumor cells, rosette formations, many interdigitating cytoplasmic processes, neurosecretory granules and microtubules, and positive immunohistochemical reactions to neurogenic markers. We describe here the first report of a peripheral PNET in a dog. Peripheral PNET should be included in the list of differential diagnoses for soft-tissue tumors in dogs.

Journal Article↗
PubMed1991

Primitive neuroectodermal tumor of the midbrain in a murine model of retinoblastoma.

The first heritable model of retinoblastoma was established by retina-specific expression of simian virus 40 T-antigen (SV40 T-ag) in transgenic mice. Bilateral, multifocal ocular tumors were observed in 100% of transgene-bearing mice. Central nervous system neoplasms occurred at a lower rate (27%) and represented the murine counterpart of human trilateral retinoblastoma. The authors characterized the transgenic brain tumors and found them to be primitive neuroectodermal tumors (PNET) of the midbrain. Murine brain tumors do not involve the pineal gland and most closely resemble undifferentiated suprasellar or parasellar tumors occasionally observed in human trilateral retinoblastoma. The murine malignancies arose from the subependymal cells of the cerebral aqueduct. Immunohistochemical and ultrastructural examination revealed that the transgenic brain tumors were undifferentiated and lacked all antigens associated with normal murine neuronal, glial, and ependymal cells.

Animals↗