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PubMed2004

Peripheral primitive neuroectodermal tumor of the chest wall of a 69-year-old man.

We report a case of peripheral primitive neuroectodermal tumor (pPNET), which belongs to the pPNET/Ewing's sarcoma family, arising in the chest wall of a 69-year-old man. He had high levels of serum neuron-specific enolase and pro-gastrin-releasing peptide, which are believed to be useful diagnostic blood markers for small cell lung carcinoma (SCLC). Microscopically, the tumor was composed of solid nests and sheets of monotous, primitive, small round cells with a few rosettes, making it difficult to distinguish from SCLC. Immunohistochemically, the tumor cells showed intense cell membranous immunoreactivity for MIC2 protein (CD99). EWS/FLI-1 chimeric mRNA that originated from the characteristic t(11;22)(q24;q12) chromosomal translocation was detected by RT-PCR and nucleotide sequence analysis. These results confirmed the diagnostic validity of the present tumor being a pPNET, thus raising the possibility that in the past, pPNETs which have arisen in the chest have been mistakenly diagnosed as SCLC.

Aged↗
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↗
PubMed2000

Neoadjuvant chemotherapy for peripheral malignant neuroectodermal tumor of bone: recent experience at the istituto rizzoli.

PURPOSE: The results achieved in 44 patients with nonmetastatic peripheral neuroectodermal tumor (PNET) of bone treated with neoadjuvant chemotherapy are reported. PATIENTS AND METHODS: A six-drug regimen of chemotherapy (vincristine, doxorubicin, dactinomycin, cyclophosphamide, ifosfamide, and etoposide) was administered to all patients. Local treatment consisted of surgery in 20 patients, surgery followed by radiotherapy in 13, and radiotherapy only in 11. RESULTS: At a mean follow-up of 4.5 years (range, 2 to 7 years), 23 patients (52%) remain event-free, 20 have relapsed (45%), and one has died of chemotherapy-related toxicity. The 5-year event-free survival and overall survival were 54.2% and 62.7%, respectively. To assess the prognostic significance of neural differentiation in the family of Ewing's sarcoma, these results have been compared with the outcomes of 138 concomitant patients with typical Ewing's sarcoma (TES) who were treated according to the same protocol. Of these, 103 (75%) remained continuously event-free, 34 (24%) relapsed, and one died of chemotherapy-related toxicity. It follows that PNET patients treated with this chemotherapy regimen have a significantly worse prognosis than typical ES patients (5-year event-free survival, 54.2% v 70.6%, P <.012; 5-year overall survival, 62.7% v 78.3%, P <.002). CONCLUSION: The authors conclude that studies into new adjuvant therapy for Ewing's sarcoma modulated according to risk of relapse should also consider neural differentiation as a risk factor.

Adolescent↗
PubMed2003

Nerve growth factor regulates neuroectodermal tumor cell responses to mitogenic growth factors.

Previous studies showed that nerve growth factor (NGF) decreases the proliferation of neuroectodermal tumor (NET) cells (C-1300 and Neuro2A murine neuroblastoma, PC12 rat pheochromocytoma) within 5-7 days in a dose-dependent manner. This effect is regulated by the concentration of serum in the culture medium. Therefore, we hypothesized that NGF exerts its antimitogenic activities by interfering with the proliferative action of other growth factors. We studied the effects of short-term vs. long-term as well as endogenous vs. exogenous NGF on NET cell proliferation in response to various mitogenic growth factors. Retrovirus-mediated transfer of the beta-NGF gene into NET cells activated TrkA and consistently decreased their proliferative responses to insulin-like growth factor (IGF)-I, IGF-II, fibroblast growth factor-2, and epidermal growth factor (EGF), down-regulating EGF and IGF-I binding sites. It also decreased tyrosine phosphorylation of ERK-1, STAT3, and EGF or IGF receptors after treatment with IGF-I or EGF. Long-term incubation of NET cells with NGF mimicked the responses induced by beta-NGF gene transfer, albeit in a reversible manner. Short-term NGF treatment augmented the proliferative responses to IGF-I or EGF by enhancing cell survival. It also increased tyrosine phosphorylation of signal transducing proteins after exposure to IGF or EGF, an effect opposite to that of long-term NGF treatments. Hence, long-term NGF exposure in vitro might better reproduce the effects of NGF in vivo than short-term treatments. Only long-term exposure to NGF decreased the responses of NET cells to mitogenic growth factors by down-regulating their receptors and attenuating signal transduction events required for cell proliferation. These results suggest that NGF could exert similar actions on cellular responses to growth factors in vivo.

Animals↗
PubMed2004

Karyotypic evolution pathways in medulloblastoma/primitive neuroectodermal tumor determined with a combination of spectral karyotyping, G-banding, and fluorescence in situ hybridization.

Medulloblastomas (MBs) or primitive neuroectodermal tumors (PNETs) represent 15%-30% of pediatric brain tumors and are the most common brain tumors in children; they are rare in adults. Classification of these tumors is based on tissue morphology and is often controversial and problematic. Karyotypic analysis of these tumors using conventional cytogenetic methods is often a difficult process that may be hindered by a limited number of metaphase cells and poor chromosome morphology, often leading to only partial characterization of the chromosomal abnormalities. We investigated three primary human tumors and four cell lines (CHO-707, DAOY, D-341, and PFSK) utilizing a combination of conventional G-banding, spectral karyotyping (SKY), and fluorescence in situ hybridization (FISH) techniques. A high level of intratumoral heterogeneity was seen, with multiple numerical and structural chromosomal aberrations. The chromosomes most frequently involved in structural aberrations were chromosomes 1 (14 rearrangements), 7 (9 rearrangements), and 21 (9 rearrangements). The chromosomes most frequently involved in numerical aberrations were chromosomes 1, 12, and 13 (four cases) and chromosomes 14, 17, 19, 21, 22, and X (three cases). Numerous aberrant chromosomes were characterized only with the SKY analysis, and based on these findings multiple clones were identified, facilitating analysis of karyotypic evolution. The most frequent evolution mechanism was via polyploidization, followed by acquisition of additional numerical or structural aberrations (or both); however, the results showed that the karyotypic evolution process in these tumors is typically divergent and complex.

Adult↗
PubMed1998

Primitive cerebral neuroectodermal tumors excluding medulloblastomas: a retrospective study of 30 cases.

We present a retrospective study of 30 cases of primitive cerebral neuroectodermal tumors (PNET), excluding medulloblastomas, referred to us postoperatively for additional therapy to evaluate prognostic factors and treatment efficiency. The histologic types were: pinealoblastomas (n = 7); ependymoblastomas (n = 2); medulloepitheliomas (n = 4), and other PNET (n = 17). The tumor was located in the supratentorial area in 24 patients and in the posterior fossa in 6 patients. Among the supratentorial tumors, 8 were metastatic. Maximal surgical resection was performed. Sixteen of 30 patients had no measurable disease after surgery and were considered as standard-risk (SR) cases, and 14 with a local residue or metastasis as high-risk (HR) cases. The objective of postsurgical treatment was to avoid radiotherapy in children below 4 years of age. It consisted of radiotherapy alone in 6 patients, chemotherapy alone in 17, and radiotherapy with chemotherapy in 7. Furthermore, high-dose chemotherapy (busulfan, thiotepa) and autologous bone marrow transplantation, performed in 6 patients, yielded a response rate of 3/6. Event-free survival (EFS) of SR patients was 37% at 3 years (95% confidence interval (CI) 14-60%) and overall survival 44% (95% CI 26-62%). Only 1 of the HR patients achieved a complete remission and all of them died early. The critical prognostic factors appear to be the completeness of initial surgical resection and absence of metastasis. These tumors have a poor prognosis. Novel strategies (high-dose chemotherapy) are needed to improve their outcome because the children concerned are very young and the effects of radiotherapy are particularly deleterious when tumors are situated in the supratentorial area.

Adolescent↗
PubMed2005

[Primitive neuroectodermal tumor arising 8 years after chemotherapy and radiotherapy for acute lymphoblastic leukemia: case report].

We report a case of primitive neuroectodermal tumor (PNET) arising 8 years after chemotherapy and radiotherapy for acute lymphoblastic leukemia. A 15-year-old boy with a history of acute lymphoblastic leukemia, at the age of 7, underwent chemotherapy and 14Gy of radiotherapy to the whole brain. He was admitted to our department due to the development of aphasia, right hemiparesis and generalized convulsive seizure. MRI showed an irregularly enhanced mass in the left frontal lobe. A gross total removal of the tumor was performed and histological examination showed it to be PNET. Postoperatively, the patient underwent 20Gy of radiotherapy to the whole brain and 42Gy of local radiotherapy. Follow-up MRI showed no evidence of recurrent tumor 4 months after the radiotherapy. This tumor was thought to be a secondary brain tumor arising in this survivor of childhood acute lymphoblastic leukemia and it is a rare complication of successful leukemia treatment.

Adolescent↗
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↗
PubMed1989

Malignant melanotic neuroectodermal tumor arising from the pineal body.

A case of a melanotic neuroectodermal tumor arising from pineal region of a 4-year-old girl is presented. The tumor had spread diffusely to the meninges, consistent with malignant behavior. Histologically, the tumor consisted primarily of epithelial elements arranged in tubules, cords and nests separated by fibrous vascular tissue in addition to a small neuroblastomatous focus. Melanin pigment was frequently observed in the epithelial tumor cells, and melanin-laden macrophages were also often observed. No teratoid elements were found. Immunohistochemically, tumor cells were positive for neuron-specific enolase but were nonreactive for S-100 protein, epithelial membrane antigen, glial fibrillary acidic protein, vimentin, alpha-fetoprotein and human chorionic gonadotrophin. Ultrastructurally, the epithelial nature of the tumor cells could be easily demonstrated. In addition, melanosomes in various stages in maturation were observed, indicating melanogenesis of the tumor. On the basis of the tumor location and the histological similarities previously observed for the fetal pineal body, it is very likely that this melanotic epithelial tumor could have originated from the fetal pineal gland.

Brain Neoplasms↗
PubMed2000

Epithelial Phenotype in Ewing's Sarcoma/Primitive Neuroectodermal Tumor.

Neural differentiation is an integral component of Ewing's sarcoma/primitive neuroectodermal tumor (PNET), which exhibits a continuous spectrum from minimal to prominent neural phenotype. Differentiation of Ewing's sarcomas/PNETs along other lineages or the expression of an epithelial phenotype is less common and-if present-may cause diagnostic difficulties. In this study we evaluated the frequency of epithelial differentiation in formalin-fixed and paraffin-embedded tissues of 33 (22 primary and 11 metastatic) Ewing's sarcomas/PNETs by using an immunohistochemical assay with several antikeratin antibodies. Focal positivity for low- or high-molecular-weight keratins was documented in 18% of the cases, and diffuse coexpression of low- and high-molecular-weight keratins was observed in two cases. Expression of the MIC-2 gene product was documented in 94% of the tumors. The primitive neural phenotype as revealed by expression of either neuron-specific enolase or synaptophysin was observed in 30% of the cases, but coexpression of both neural markers was present in only 15% of the tumors. This study documents that, in addition to primitive neural differentiation, Ewing's sarcomas/PNETs frequently exhibit focal positivity for keratins, with rare strong diffuse coexpression of both low- and high-molecular-weight keratins. The findings indicate that the expression of an epithelial phenotype, at least in a focal fashion, is a relatively frequent finding in otherwise typical Ewing's sarcomas/PNETs. Int J Surg Pathol 8(1):59-65, 2000

Journal Article↗
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↗
PubMed2000

Melanotic neuroectodermal tumor of infancy (MNTI) of the hard palate: presentation and management.

OBJECTIVE: To discuss the presentation and management of melanotic neuroectodermal tumor of infancy (MNTI) of the hard palate. METHOD: Case presentation and literature review. CASE: A 6-month-old girl presented with a slow growing, non-tender anterior oral hard palate mass. Radiologic imaging revealed a well-circumscribed cystic lesion containing teeth. After excision, histopathologic and electron microscopic evaluation revealed MNTI. No recurrence was seen at 12-month follow-up. CONCLUSIONS: This case and a review of the literature reveal MNTI to be a rare, benign hard palate tumor, which may present as a smooth, firm, painless, slow-growing anterior palatal lesion. Imaging reveals a well-circumscribed cystic lesion. Complete excision should be curative. Management requires attention to the potential need for palatal reconstruction, orthodontic care and correction of secondary nasal deformities.

Female↗
PubMed1992

Peripheral primitive neuroectodermal tumors. Diagnosis, classification, and prognosis.

In conclusion, the group of peripheral primitive neuroectodermal tumors has been redefined in recent years on the basis of cytogenetic, molecular genetic and more precisely defined histopathologic characteristics. Although in the past, many tumors has been called Ewing's sarcoma, currently this diagnosis is limited to tumors which cannot be more specifically classified on the basis of their ultrastructural and immunophenotypic characteristics. Most small round cell tumors previously classified as Ewing's sarcoma are now classified as peripheral PNET. The consistent cytogenetic abnormality in Ewing's sarcoma and peripheral PNET and patterns of neurotransmitter enzymes have supported a common neuroectodermal origin. The precise characterization of soft tissue Ewing's sarcoma is further complicated by the several primitive rhabdomyosarcomas that may exhibit a similar light microscopic appearance. The importance of histopathologic distinction among these various round cell tumors of childhood is well recognized. Furthermore, primitive tumors with overlapping neural and mesenchymal features, known as malignant ectomesenchymoma, are now identified more often than previously. Finally, molecular biologic and cytogenetic differences between peripheral PNET and neuroblastoma have confirmed their clinical and biologic differences, in spite of their morphologic similarities. Molecular genetic and flow cytometric evaluation have contributed to the distinction of groups with prognostic significance and offer possibilities for new clinical trials.

Adolescent↗
PubMed2002

Incidence and trends in pediatric malignancies medulloblastoma/primitive neuroectodermal tumor: a SEER update. Surveillance Epidemiology and End Results.

BACKGROUND: It has been suggested that cerebellar medulloblastoma (M) and primitive neuroectodermal tumors (PNET) arising elsewhere in the nervous system, represent a single entity (M/PNET), although this concept is controversial. Cancer registries permit population-based description of cases reported as medulloblastoma, those reported as PNET and description of the aggregate, M/PNET. PROCEDURE: We reviewed the 768 cases of M/PNET (633 diagnosed medulloblastoma and 135 diagnosed PNET) among persons under 20 years of age in the National Cancer Institute's Surveillance Epidemiology and End Results (SEER) database. RESULTS: The incidence of M/PNET rose 23%, from 4 per 10(6) person-years in 1973-77 to 4.9 per 10(6) person-years in 1993-98. Cases reported as PNET were more likely than those reported as medulloblastoma to be supratentorial (30.4% vs. 1.9%, P < 0.001) and to be female (42.2% vs. 35.4%, P = 0.13). The difference in 5-year survival between the 600 children with infratentorial medulloblastoma vs. the 49 children with infratentorial PNET was not statistically significant (55% vs. 43%). Regardless of reporting diagnosis, survival was poorer among children age 0-3 years and those with supratentorial tumors. Children diagnosed in the more recent period from 1985-1998 had a longer median survival than children diagnosed in 1973-84 (4.9 years vs. 10 years, P < 0.05). Rates were 42% higher among Whites compared to Blacks (4.5/10(6) person-years vs. 3.1/10(6) person-years, P < 0.01). CONCLUSIONS: We found M/PNET is increasing in incidence and more frequent among Whites. Given that medulloblastoma and PNET are histologically identical and have similar epidemiologic profiles, future studies should provide analyses that combine these entities.

Adolescent↗
PubMed2005

Supratentorial primitive neuroectodermal tumors (S-PNET) in children: A prospective experience with adjuvant intensive chemotherapy and hyperfractionated accelerated radiotherapy.

PURPOSE: Supratentorial primitive neuroectodermal tumors (S-PNET) are rare and have a grim prognosis, frequently taking an aggressive course with local relapse and metastatic spread. We report the results of a mono-institutional therapeutic trial. METHODS AND MATERIALS: We enrolled 15 consecutive patients to preradiation chemotherapy (CT) consisting of high-dose methotrexate, high-dose etoposide, high-dose cyclophosphamide, and high-dose carboplatin, craniospinal irradiation (CSI) with hyperfractionated accelerated radiotherapy (HART) plus focal boost, maintenance with vincristine/lomustine or consolidation with high-dose thiotepa followed by autologous stem-cell rescue. RESULTS: Median age was 9 years; 7 were male, 8 female. Site of disease was pineal in 3, elsewhere in 12. Six patients were had no evidence of disease after surgery (NED). Of those with evidence of disease after surgery (ED), 2 had central nervous system spread. Of the 9 ED patients, 2 had complete response (CR) and 2 partial response (PR) after CT, 4 stable disease, and 1 progressive disease. Of the 7 ED patients before radiotherapy, 1 had CR, 4 PR, and 2 minor response, thus obtaining a 44% CR + PR after CT and 71% after HART. Because of rapid progression in 2 of the first 5 patients, high-dose thiotepa was systematically adopted after HART in the subsequent 10 patients. Six of 15 patients relapsed (4 locally, 1 locally with dissemination, 1 with dissemination) a mean of 6 months after starting CT, 2 developed second tumors; 5 of 6 relapsers died at a median of 13 months. Three-year progression-free survival, event-free survival, and overall survival were 54%, 34%, and 61%, respectively. CONCLUSION: Hyperfractionated accelerated RT was the main tool in obtaining responses in S-PNET; introducing the myeloablative phase improved the prognosis (3/10 vs. 3/5 relapses), though the outcome remained unsatisfactory despite the adoption of this intensive treatment.

Adolescent↗
PubMed2006

Primary pulmonary primitive neuroectodermal tumor: CT and skeletal scintigraphic image features with pathologic correlation (2006: 6b).

We describe a rare case of a primitive neuroectodermal tumor (PNET) originating in the lung of a 28-year-old woman. A lung mass was detected incidentally on a chest radiograph taken before a Caesarian delivery. The chest P-A view showed a well-defined, lobulated mass in the right lower lobe with a small pleural effusion on the right. A thoracic CT with contrast enhancement showed a lobulated, heterogeneous, enhanced mass of approximately 9.2 x 8.4 x 6.3 cm with inner amorphous calcifications in the right lower lobe and a small right pleural effusion. A right lower lobectomy was performed 1 month after delivery. The pathology report was a primary pulmonary PNET with focal visceral pleural involvement.

Adult↗
PubMed1998

Basimeningeal/spinal axis primitive neuroectodermal tumor without intraaxial lesion: radiological features.

Over a 12-year period, the authors encountered 2 patients with spinal axis/basimeningeal primitive neuroectodermal tumor (PNET) involving the spinal axis extramedullary, intradural compartment and the basimeninges. In neither patient was an intraaxial focus demonstrated. A 48-year-old woman had computed tomography (CT) findings of hydrocephalus and later abnormal basimeningeal enhancement. Cervical myelography revealed a low cervical intradural block. A 10-year-old boy was evaluated initially with non-contrast-enhanced CT of the brain, which revealed hydrocephalus. Contrast-enhanced CT revealed abnormal basimeningeal enhancement implicating cisternal obstruction. Subsequent magnetic resonance examination of the entire spine with and without gadolinium enhancement revealed diffuse abnormal enhancement of the spinal axis intradural, extramedullary compartment. While intraaxial PNETs are well recognized, the patients described here represent a distinctly unusual pattern of intradural spinal meningeal and basimeningeal infiltration by PNET in the absence of a demonstrable intraaxial lesion.

Brain Neoplasms↗