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PubMed2004

Primary primitive neuroectodermal tumor within the spinal epidural space: report of a case and review of the literature.

Primary intraspinal primitive neuroectodermal tumors (PNETs) are rare tumors and a have poor prognosis. In reviews of the literature, it is seen that primary intraspinal PNETs may arise at all levels of the spine and may be intramedullary, intradural-extramedullary, or epidural. Spinal epidural location of PNET is extremely rare and out of 22 cases of primary spinal PNETs reported to date, only two were epidural. Tumors within the epidural space of the spinal canal are most often metastatic neoplasms from different primary sites. Here we report a case of primary extradural PNET located in the thoracic spine in a 16-year-old boy and review the relevant literature.

Adolescent↗
PubMed1999

Comparison of CSF cytology and spinal magnetic resonance imaging in the detection of leptomeningeal disease in pediatric medulloblastoma or primitive neuroectodermal tumor.

PURPOSE: Leptomeningeal disease (LMD) significantly affects the prognosis and treatment of pediatric patients with medulloblastoma or primitive neuroectodermal tumor (PNET). Examination of CSF for malignant cells, detection of LMD on spinal magnetic resonance imaging (MRI), or both are the methods routinely used to diagnose LMD. A recent study suggested 100% correlation between CSF and MRI findings in children with medulloblastoma. To determine the validity of this hypothesis, we compared the rate of detection of LMD between concurrent lumbar CSF cytology and spinal MRI performed at diagnosis in patients with medulloblastoma or PNET. PATIENTS AND METHODS: As a part of diagnostic staging, 106 consecutive patients newly diagnosed with medulloblastoma or PNET were evaluated with concurrent lumbar CSF cytology and spinal MRI. CSF cytology was examined for the presence of malignant cells and spinal MRI was reviewed independently for the presence of LMD. RESULTS: Thirty-four patients (32%) were diagnosed with LMD based on CSF cytology, spinal MRI, or both. There were 21 discordant results. Nine patients (8.5%) with positive MRI had negative CSF cytology. Twelve patients (11.3%) with positive CSF cytology had negative MRIs. The exact 95% upper bounds on the proportion of patients with LMD whose disease would have gone undetected using either CSF cytology or MRI as the only diagnostic modality were calculated at 14.4% and 17.7%, respectively. CONCLUSION: With the use of either CSF cytology or spinal MRI alone, LMD would be missed in up to 14% to 18% of patients with medulloblastoma or PNET. Thus, both CSF cytology and spinal MRI should routinely be used to diagnose LMD in patients with medulloblastoma or PNET.

Adolescent↗
PubMed1994

"Undifferentiated" cerebral primitive neuroectodermal tumor in a young adult--case report.

A 21-year-old female presented with a cerebral primitive neuroectodermal tumor (PNET) without either glial or neuronal differentiation, who has survived for 27 months without neurological deficit following total removal of the tumor, radiotherapy, and intensive chemotherapy. Both immunohistochemical and ultrastructural studies are important for the diagnosis of PNET. "Undifferentiated" PNET may be a distinct entity from common PNET which shows either glial or neuronal differentiation or both.

Adult↗
PubMed2005

Supratentorial primitive neuroectodermal tumor in an aged patient--case report--.

An 88-year-old woman presented with a supratentorial primitive neuroectodermal tumor (PNET) manifesting as disturbance of consciousness and left hemiplegia. Magnetic resonance imaging showed a large mass lesion in the right frontotemporal region. She underwent biopsy of the lesion that confirmed the diagnosis of PNET. Her poor condition only allowed chemotherapy with methyl 6-[3-(2-chloroethyl)-3-nitrosoureido]-6-deoxy-alpha-D-glucopyranoside (MCNU), vincristine, and prednisolone to be performed. The patient died approximately 6 months after diagnosis due to enlargement of the tumor. Supratentorial PNET is a rare tumor, especially in adults. Multimodal therapy consisting of gross total or subtotal resection, radiation therapy, and chemotherapy is generally considered necessary for patients with supratentorial PNET. However, the condition of each patient should be considered in determining the therapeutic plan, especially in the case of extremely aged patients, since supratentorial PNET is malignant and long-term survival is rare despite aggressive treatment.

Aged, 80 and over↗
PubMed1998

[A clinicopathological analysis of primitive neuroectodermal tumors of the CNS].

OBJECTIVE: To investigate the difference between cerebellar medulloblastoma (MB) and primary cerebral small cell tumor in histogenesis, morphologic features and biological behavior. METHODS: 210 cases of MB and 9 cases of small cell tumor of cerebrum were observed with histologic and immunohistochemical techniques. RESULTS: Both tumors were composed of primitive cells with focal evidence of glial and/or neuronal differentiation. In 63.2% of MB and five-eighths of small cell tumor of cerebrum coexpressed GFAP and Syn. Both types of tumors were highly malignant. The overall 1 year survival rates were 34.63% and 25.65% respectively. The survival rate was lower for patients with high proliferative index, with necrosis or without receiving radiation therapy. CONCLUSION: MB is similar to other small cell tumors of CNS in morphological features, specific marker expression and biological behavior. These tumors can be classified as primitive neuro-ectodermal tumors (PNET).

Adolescent↗
PubMedDate not supplied

Primitive neuroectodermal tumors of the cauda equina in adults with no detectable primary intracranial neoplasm--three case studies.

We studied three cases of primitive neuroectodermal tumors surgically removed from the cauda equina region of adults. There was no clinical or radiological evidence of cerebellar medulloblastoma, other intracranial tumor or paraspinal sympathetic neuroblastoma. Two patients died: autopsies revealed no primary intracranial neoplasm. One patient is alive 3 years after surgery with no detectable intracranial tumor. The tumors had the light and electron microscopic features of primitive neuroectodermal tumors as described earlier in the literature. In addition, in all three cases many tumor cells could be stained for cytoplasmic neurofilament antigen.

Adult↗
PubMedDate not supplied

Spinal metastasis in primitive neuroectodermal tumors (medulloblastoma) of the posterior fossa: evaluation with CT myelography and correlation with patient age and tumor differentiation.

Twelve consecutive children with primitive neuroectodermal tumors of the posterior fossa (PNET-PF) were evaluated for spinal metastases with CT metrizamide myelography (CTMM) in the early postoperative period. Metastases were identified in 5 children (42%) and all were noted to have deposits in the thoracic region. All children with metastases were less than 3 years old and had differentiated PNET-PF.

Adolescent↗
PubMed2000

Molecular insight into medulloblastoma and central nervous system primitive neuroectodermal tumor biology from hereditary syndromes: a review.

Through the study of uncommon familial syndromes, physicians and scientists have been able to illuminate the underlying mechanisms of some of the more common sporadic diseases; this is illustrated best by studies of familial retinoblastoma. A number of rare familial syndromes have been described in which affected individuals are at increased risk of developing medulloblastoma and/or supratentorial primitive neuroectodermal tumors. The descriptions of many of these syndromes are based on patients observed by clinicians in their clinical practice. Determination of the underlying genetic defects in these patients with uncommon syndromes has led to identification of a number of genes subsequently found to be mutated in sporadic medulloblastomas (tumor suppressor genes). Associated genes in the same signaling pathways have also been found to be abnormal in sporadic medulloblastoma. Identification of patients with these rare syndromes is important, as they are often at increased risk for additional neoplasms, as are family members and future children. We review the published literature describing hereditary syndromes that have been associated with an increased incidence of medulloblastoma and/or central nervous system primitive neuroectodermal tumor. Review of the underlying molecular abnormalities in comparison to changes found in sporadic neoplasms suggests pathways important for tumorigenesis.

Central Nervous System Neoplasms↗
PubMed1986

A new staging method versus TNM staging in children with posterior fossa primitive neuroectodermal tumor (medulloblastoma).

Prognostic factors were evaluated in 30 children with primitive neuroectodermal tumors of the posterior fossa (classical medulloblastoma or differentiated medulloblastoma). The preoperative TNM (Tumor, Node, Metastasis) staging system has been applied to estimate prognosis of patients with central nervous system tumors, but this system was not applicable in assessing the postoperative status of the tumor. To fill this need, a postoperative staging system was developed known as MAPS (Metastasis, Age, Pathology, Surgery), and in this report its efficacy is compared with that of the TNM system. The predictive values of MAPS staging in these 30 children were better than those obtained using the TNM method (MAPS r2 = -0.90; TNM r2 = 0.73; P less than 0.05).

Age Factors↗
PubMed1991

Immunohistochemistry of primitive neuroectodermal tumors in infants with special emphasis on cytokeratin expression.

Eleven primitive neuroectodermal tumor (PNET) biopsies from infants under the age of 3 years were studied for the presence of various differentiation markers for neuroectodermal stem cells. Special emphasis was placed on the expression of cytokeratin proteins. The tumor cells expressed different cytokeratin proteins (CK8, CK13, CK18, CK19, KL1, AE1/AE3, MNF16) in 3 of 11 cases. These cases were furthermore characterized by a strong expression of glial fibrillary acidic protein, S-100 protein and vimentin. Vimentin and cytokeratin proteins were co-expressed; cross-reactivity between these two intermediate filaments could be excluded by immunoblotting. It is noteworthy that the three positive tumors were all from infants in their 1st year. We assume that PNETs in early infancy are characterized by a particularly wide range of differentiation patterns. The presence of cytokeratin proteins in these cases seems to be associated with the expression of vimentin and must be regarded as an indicator of an early developmental stage of the tumor cells.

Child, Preschool↗
PubMed1991

Cytokeratin expression in a congenital multipotential primitive neuroectodermal tumor.

A case of an uncommon congenital primitive neuroectodermal cerebellar tumor (PNET) in a 5-month-old child is reported. After subtotal surgical resection, the residual tumor did not respond to radiation and chemotherapy. Histologically, the tumor was composed of small, round, undifferentiated cells and several other patterns like astrocytomatous, oligodendrogliomatous, and ependymomatous structures. Immunostaining was positive for most of the cells for vimentin and S 100, fewer were positive for glial fibrillary acid protein (GFAP) and neuron-specific enolase, and only a few for synaptophysin. Surprisingly, the tumor showed strong expression of several monoclonal cytokeratins (CK) with different molecular weights, together with epithelial membrane antigen. Furthermore, we found a coexpression of the tumor cells for CK and vimentin, while CK-GFAP and CK-S 100 were negative. Ultrastructurally, intracytoplasmic intermediate filaments could be observed corresponding to immunohistochemical CK expression. The very strong CK and vimentin expression in this case was interpreted as a sign of the embryonic nature of the tumor.

Biomarkers, Tumor↗
PubMed1992

Understanding the radiology of intracranial primitive neuroectodermal tumors from a pathological perspective: a review.

The concept of primitive neuroectodermal tumors (PNETs) has been controversial since its introduction in 1973. Understanding these tumors is important for the neuroradiologist, because certain radiological features may suggest their diagnosis. A review of the PNET concept, as well as the different types of intracranial PNETs is made, using as a framework the cytogenesis of the brain. Emphasis is given to pathologic features, as they ultimately determine radiologic findings. Supratentorial PNETs are large, bulky, heterogeneous masses with "cystic" (necrotic) areas, calcification, and very little edema. Infratentorial PNETs are generally less heterogeneous, but the larger tumors tend to be more cystic, necrotic, and calcific, resembling supratentorial PNETs.

Adult↗
PubMed2005

Peripheral primitive neuroectodermal tumor associated with the anterior mandible: a case report and review of the literature.

Neuroectodermal tumors may arise in many places throughout the body including the diverse tissues of the head and neck. The primitive neuroectodermal tumor is a predominately neural, nonepithelial neoplasm similar to Ewing sarcoma. This article describes an 18-year-old female patient with a highly malignant peripheral primitive neuroectodermal tumor located in the soft tissue anterior to the mandibular symphysis. The clinical and radiographic presentation as well as the histopathology and immunohistochemistry of this rare entity is discussed. A review of the literature with respect to this tumor, as well as the current management of this tumor, is presented.

12E7 Antigen↗
PubMedDate not supplied

Intrasellar primitive neuroectodermal tumor (PNET) in familial retinoblastoma: a variant of "trilateral retinoblastoma".

An infant with bilateral familial retinoblastomas was found at age 6 months to have a large mass within the region of the sella turcica. The histology, immunoreactivity and ultrastructure of the tumor showed primitive neuroectodermal cells. A small number of cells showed positive immunostaining to retinal S antigen. This represents a rare form of so-called trilateral retinoblastoma. In most cases of trilateral retinoblastoma, the intracranial non-metastatic tumor is within the pineal gland. The occurrence of such a tumor in the region of sella turcica is very unusual and its possible significance is discussed in regard to our current understanding of the susceptibility to carcinogenesis conferred by inheritance of the mutant retinoblastoma gene, Rb-1.

Antigens↗
PubMed1997

Primitive neuroectodermal tumor of the kidney--another enigma: a pathologic, immunohistochemical, and molecular diagnostic study.

Primitive neuroectodermal tumor (PNET), the second most common type of sarcoma in the first two decades of life, rarely presents as an organ-based neoplasm. Rather, it is seen typically in the soft tissues of the chest wall and paraspinal region. We report a case of primary PNET of the kidney in a 17-year-old girl who presented with abdominal pain, hematuria, and an abdominal mass. Nodules and sheets of monotonous-appearing primitive round cells and the formation of rosettes focally were the principal microscopic features. The tumor cells were uniformly immunoreactive for vimentin, cytokeratin, neuron-specific enolase, and 013 (CD99). In addition, the characteristic translocation of PNET and Ewing sarcoma, t(11;22)(q24;q12), was detected by polymerase chain reaction (PCR). Eight previous examples of renal PNET have been reported in the literature in the past 2 years, but only three of these cases have had complete immunohistochemical evaluation with the demonstration of 013 positivity. To our knowledge the present case is the only one to date demonstrating the recurrent translocation t(11;22)(q24;q12) by PCR. Assuming that the previous cases in the literature are bona fide examples of PNET, the kidney may be another site of predilection for this usual soft-tissue neoplasm. We are once again confronted with the dilemma about the nature of the progenitor cell.

12E7 Antigen↗
PubMed2004

MRI features of intracranial primitive neuroectodermal tumors in adults: comparing with histopathological findings.

The MRI appearances of 7 adult patients with pathologically proven intracranial primitive neuroectodermal tumors (PNET) were retrospectively analyzed. The MRI features were compared with findings in pathology and surgery. In this group, the tumor masses were most commonly found in the semisphere of cerebrum and in the vermis of cerebellum. They were relatively large and 4 were in lobulated shape. All of them had well-defined margins. MR images showed the tumors to be mildly or obviously hypointense on T1-weighted images and hyperintense on T2-weighted images. Most masses had heterogeneous appearances with some cystic and necrotic areas. Intratumoral haemorrhage and focal calcification were occasionally seen. Mostly, there was no or only mild surrounding edema. Marked inhomogeneous contrast enhancement on MRI was seen in 6 cases except one. Two patients with multiple intracranial metastases were revealed on MR images. In this series, there was good correlation between MRI features and findings in pathology and surgery. These results showed that certain MRI features might suggest the diagnosis of intracranial PNET in adults. MRI is an effective technique to detect these tumors and is helpful to treatment planning and follow-up.

Adult↗
PubMed2004

Estrogen receptor expression in a human primitive neuroectodermal tumor cell line from the cerebral cortex: estrogen stimulates rapid ERK1/2 activation and receptor-dependent cell migration.

Primitive neuroectodermal tumors (PNETs) are the most common form of pediatric brain tumor. Most often these malignant childhood brain tumors arise from neuroepithelial precursor cells in the cerebellum, and less frequently in the cerebral cortex. Because the normal PNET precursor cells from the cerebrum and cerebellum transiently express high levels of estrogen receptors (ERs), we hypothesized that the PNET cells of the cerebrocortical-derived cell line PFSK1 may also express ERs and would be responsive to estrogen. Results of immunoblot studies using ER-specific antiserum indicate that both ERalpha and ERbeta are expressed in PFSK1 cells. The ability of estrogen to rapidly activate MAPK signaling was tested; low physiological concentrations of E(2) stimulated ERK1/2 phosphorylation and nuclear translocation within 15min of exposure. Exogenously added 17beta-estradiol (E(2)) could not stimulate PFSK1 growth, however E(2) significantly increased PFSK1 cell migration, suggesting that rapid actions of E(2) and ER-mediated processes might contribute to the metastatic phenotype of some PNETs.

Animals↗
PubMed2004

Congenital peripheral primitive neuroectodermal tumor refractory to treatment.

The authors report an unusual case of an infant presenting with a congenital peripheral primitive neuroectodermal tumor (PPNET) of the left hand refractory to treatment. A newborn girl was born with a large bluish-red mass of 4.5 cm diameter protruding into the palm and the dorsum of the left hand. Tumor biopsy confirmed the diagnosis of PPNET. The initial metastatic workup for the detection of metastases was negative. Four cycles of chemotherapy according to CCSG 7881/POG 8850 regimen B were given. Despite this aggressive chemotherapy the tumor grew to involve the entire left hand. The left hand was amputated, and then two cycles of topotecan/cyclophosphamide were given. Five months later extensive metastases developed, involving the brain, lungs, liver, and skeleton, and the child died at the age of 2.5 years. PPNET presenting at birth is uncommon; presentation in the hand is unusual, and the fact that it did not respond to treatment is still more uncommon.

Amputation, Surgical↗