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PubMed1998

Peripheral primitive neuroectodermal tumour of the lung: report of two cases.

AIMS: We report two unusual cases of intrapulmonary small round cell tumour with evidence that they are primitive neuroectodermal tumours. METHODS AND RESULTS: The patients were a 25-year-old woman and a 15-year-old man, in whom mass shadows were found by routine chest radiography. Both tumours were located in the pulmonary parenchyma, and there was no evidence of an extrapulmonary involvement by the tumour. The lesions showed morphological and immunophenotypic features consistent with peripheral primitive neuroectodermal tumour (pPNET). These features included a hypercellular diffuse growth pattern of closely packed small round cells occasionally forming abortive Homer-Wright-type rosettes and intense immuroreactivities to neurone-specific enolase and MIC2 gene product (O13). Unusual chondroid foci were present in one of the cases. This diagnosis was further supported by the cytogenetic and reverse transcriptase-polymerase chain reaction (RT-PCR) findings of the characteristic t(11;22) chromosomal translocation and EWS/FLI-1 fusion transcripts, respectively, in one of the cases. CONCLUSIONS: These morphological and cytogenetic findings substantiate pPNET as a subtype of intrapulmonary small round cell tumours.

Adolescent↗

PubMed1997

Cerebral primitive neuro-ectodermal tumour following treatment of a unilateral retinoblastoma.

Cerebral primitive neuro-ectodermal tumour (PNET) occurring as a second primary malignancy in childhood is exceedingly rare. We present a 7-year-old boy who developed a proven supratentorial PNET five years after enucleation and radio-/chemotherapy for a sporadic, unilateral retinoblastoma with optic nerve invasion. The association with this malignant eye disease as well as the effect of irradiation and multi-agent chemotherapy on second tumour induction are evaluated.

Chemotherapy, Adjuvant↗

PubMed1981

Soft tissue sarcomas of childhood: the differential diagnostic dilemma of the small blue cell.

In its histologic features, embryonal rhabdomyosarcoma (RMS), the prototype of malignant soft tissue tumors in childhood, summarizes the problems associated with the diagnosis of this entire group of neoplasms. Many of the tumors that do not fulfill the criteria for RMS have been designated "sarcomas of uncertain histogenesis." The introduction of the concept of a soft tissue equivalent of Ewing's sarcoma may have eased the semantic anxiety without improving our conceptual understanding. It is thought that the embryonal RMS, Ewing's sarcoma, and other are derived from a primitive mesenchymal cell. Another separate category of "small blue cell tumors" are those which presumably originate from the primitive neuroepithelium. Some of the diagnostic terms applied to this category are "neuroepithelioma," "medulloepithelioma," and "peripheral neuroblastoma." Because most of these tumors are hormonally inactive and electron microscopy is not performed, the diagnosis is infrequently considered or proved. The recently described small cell tumor of thoracopulmonary origin is likely a malignant neuroepithelial neoplasm. Hematopoietic tumors, such as non-Hodgkin's malignant lymphomas, granulocytic sarcoma, and malignant histiocytosis, may appear in the soft tissues as the initial manifestation of these system diseases. A final group of malignant soft tissue tumors are the fibrohistiocytic ones with a biphasic pattern of small round cells and spindle cells. It now has become increasingly difficult for the pathologist to satisfy his clinical colleagues with the diagnosis of "undifferentiated malignant tumor" in a child.

Bone Neoplasms↗

PubMed1998

Supratentorial primitive neuroectodermal tumours: a report of four cases with an unusual clinical course in one patient.

Four children, who were treated for supratentorial primitive neuro-ectodermal tumours between 1986 and 1995 at Kyushu University Hospital, are here presented. The initial characteristic symptoms and signs of these patients included vomiting and headache, followed by motor weakness. All patients underwent direct surgery for their tumours while 2 also received a course of postoperative radio-therapy. After these treatments, 3 died within 4 months after diagnosis, whereas one infant, who underwent a total removal of the tumour but had no adjuvant therapy, is still alive after a follow-up period of 4 years. Most of the tumour cells of these 4 cases were poorly differentiated neuro-ectodermal cells, but some also showed variable differentiation along the glial and/or neuronal lines. While such differentiation had no impact on the clinical course of the patients, the malignant potential as assessed by the percentage of MIB1-positive cells showed a good correlation with the clinical features; the 3 cases with a rapid clinical course had MIB1 staining indices of more than 2%, and one case, who survived more than 4 years, had the same indices of 0.2% as found in benign tumours. Although "PNETs" of Hart and Earl share certain clinical features, they may be a group of tumours heterogeneous in their origins, histogenesis, and biological behaviours.

Biomarkers, Tumor↗

PubMedDate not supplied

Malignant teratoid medulloepithelioma in eye.

Malignant teratoid medulloepithelioma is an extremely rare tumor occurring in children younger than 5 years of age, arising from ciliary body epithelium or iris but few arise from optic nerve and retina. This report concerns a 5 years old boy who presented with pain, redness and protrusion of right eye. Histopathologically, the tumor was composed of epithelial and sarcomatoid component. The pseudostratified primitive appearing epithelial cells were arranged mainly in diffuse pattern, nests cords and tubules. At places, pseudo rosette and true rosette were seen. Mitoses were frequent consisting of 7-10/ HPF. The sarcomatoid component consisting of spindle shaped cells arranged in interlacing bundle were also seen. Mitoses counted 5-7/HPF. Massive areas of necrosis and hemorrhage along with calcification, focal area of mature cartilage were present. Vascular and optic nerve invasions were seen. This case of malignant teratoid medulloepithelioma is the second case diagnosed in TU Teaching Hospital within the period of 10 years and reported because of its rarity. The differentiations from other tumors of the orbit such as small cell tumor were discussed.

Child↗

PubMed1975

An experimental mouse testicular teratoma as a model for neuroepithelial neoplasia and differentiation. I. Light microscopic and tissue and organ culture observations.

The various stages of divergent neuroepithelial differentiation were studied in the solid transplants of a transplantable mouse testicular teratoma (OTT-6050) maintained in both ascitic and solid forms. They included: a) areas of undifferentiated medullary epithelium corresponding to the rare human medulloepithelioma; b) areas of neuroblastic differentiation corresponding to neuroblastoma, with more mature neuronal differentiation corresponding to ganglioneuroma or, when mixed with glial elements, to ganglioglioma; and c) more mature neuroglial areas resembling astrocytoma, oligodendroglioma or ependymoma, as well as more primitive areas corresponding to ependymoblastoma. In tissue culture using collagen-coated coverslips, astrocytic differentiation was found in the outgrowth zone after 15 days, confirmed by immunofluorescence with antibodies to an astroglia-specific protein. In organ culture systems, glial components, including ependymal structures, were preserved in tumor explants, and astrocytic differentiation, as expressed by glial fiber formation, was increased after 4 to 6 weeks in vitro. No neuronal differentiation was demonstrable, however. The neuroepithelial component of this experimental teratoma may provide a model for the study of neoplastic neuroepithelial differentiation.

Animals↗

PubMed2004

Primary primitive neuro-ectodermal tumor of cauda equina with intracranial seeding.

Primitive neuro-ectodermal tumor (PNET) of the cauda equina is a rare entity. 18 cases have been reported in the literature so far, including 4 cases with intracranial seeding. Moreover parenchymal involvement of brain has never been reported as a form of intracranial seeding from PNET of the cauda equina. A 31 year-old female patient, with PNET of cauda equina showing intracranial seeding 6 months after surgery, is presented in this report. To our knowledge, this is the first adult case of spinal cord PNET with parenchymal involvement of brain. The histopathological, clinical and radiological findings as well as treatment of the patient were evaluated.

Adult↗

PubMed2005

A comparison between in vivo and ex vivo HR-MAS 1H MR spectra of a pediatric posterior fossa lesion.

The present case report was aimed at identifying the molecular profile characteristic of a primitive neuro-ectodermal tumor (PNET) in a 3-year-old child affected by a lesion localized in the cerebellar region. The histological diagnosis was medulloblastoma. In vivo single voxel 1H magnetic resonance spectroscopy (MRS) shows high specificity in detecting the main metabolic alterations in the primitive cerebellar lesion; a very high amount of the choline-containing compounds and very low level of creatine derivatives and N-acetylaspartate. Ex vivo high resolution magic angle spinning (HR-MAS) 1H magnetic resonance spectroscopy, performed at 9.4 Tesla on the neoplastic specimen collected during surgery, allows for the unambiguous identification of several metabolites giving a more in-depth evaluation of the metabolic pattern of the lesion. The ex vivo HR-MAS MR spectra show that the spectral detail is much higher than that obtained in vivo and that, for example, myo-inositol, taurine and phosphorylethanolamine contribute to the in vivo signal at 3.2 ppm, usually attributed to choline-containing compounds. In addition, the spectroscopic data appear to correlate with some morphological features of the medulloblastoma. Consequently, the present study shows that ex vivo HR-MAS 1H MRS is able to strongly improve the clinical possibility of in vivo MRS and can be used in conjunction with in vivo spectroscopy for clinical purposes.

CD56 Antigen↗

PubMed2002

Features of proliferation and in vitro drug resistance in central primitive neuro-ectodermal tumours.

The features of proliferation in brain tumours are related with clinical prognosis for several types of brain tumours, especially gliomas. For childhood central primitive neuro-ectodermal tumours (cPNET), including medulloblastoma, this relation has previously been unclear. The aim of this study is to investigate the relationship between proliferative features of cPNET and in vitro resistance for cytostatic drugs measured with the 3-4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium-bromide (MTT) assay. Tumour material was obtained from 23 surgical specimens of cPNET. The expression of the proliferation markers Ki-67, proliferating cell nuclear antigen (PCNA) and cyclin D1 was determined with immunohistochemistry, while S-phase and DNA ploidy were analysed by flowcytometric analysis cell scan (FACS). The in vitro resistance for 10 cytostatic drugs was determined with the MTT assay. Drug resistance levels were available in 19 (83%) of the 23 samples with a complete profile of 10 cytostatic drugs tested in 14 samples. An excellent correlation in drug resistance scores was found between pharmacologically related drugs. The Ki-67 staining in 20 samples varied from 10 to 60% and from 30 to 100% for PCNA. Cyclin D1 staining was negative in 11 out of 18 samples. The S-phase in 16 samples ranged from 2 to 16%. Increased staining of Ki-67 was related with actinomycin D sensitivity (r -.603; P=0.022), while cells with a higher S-phase percentage were more resistant to ifosfamide (r.952; P<0.0001). In vitro drug resistance testing of central primitive neuro-ectodermal tumours (PNET) is feasible with the MTT assay. Ifosfamide resistance was related with increased Ki-67 and S-phase percentage of the tumour cells, while increased Ki-67 was also related with actinomycin D sensitivity. These findings suggest a cell cycle dependent activity of cytostatic drugs in vitro.

Antineoplastic Agents↗

PubMed1998

Primary primitive neuroectodermal tumour of the parotid gland.

AIMS: Primitive neuroectodermal tumour (PNET) is a malignant small round cell tumour that exhibits neuroepithelial differentiation. Isolated cases of PNET have been reported in visceral sites such as the kidney, uterus, ovary, testis, urinary bladder and pancreas. We present two cases of PNET of the parotid gland. METHODS AND RESULTS: The first case was a 60-year-old woman, who presented with a parotid swelling of 10 months duration. The second case was a 45-year-old man, who presented with a recurrent temporofacial swelling of 6 months duration. Histological evaluation, in conjunction with immunohistochemistry, confirmed the diagnosis of PNET. CONCLUSIONS: This is the first documentation of PNET of the salivary gland. The probable origin is from the facial nerve.

Biomarkers, Tumor↗

PubMed1995

Peripheral primitive neuroectodermal tumour after allogeneic bone marrow transplantation.

We report a case of peripheral primitive neuroectodermal tumour (PNET) in a 36-year-old man who 10 years earlier received an allogeneic bone marrow transplantation (BMT) for a non-Hodgkin's lymphoma. Immunohistochemistry proved definitive elimination of a relapse of the original disease and confirmed the diagnosis of PNET. The role of total body irradiation pre-BMT in the genesis of this secondary tumour is discussed. The importance of registering secondary malignant solid tumours after BMT is emphasized. To our knowledge, an Ewing family tumour following BMT has not previously been reported.

Adult↗

PubMed1992

Ectopic intrapelvic medulloepithelioma: case report.

A primary extraspinal medulloepithelioma with lung metastases is reported. The tumour was located in the presacral area. Microscopically, it showed typical features of medulloepithelioma with focal ependymal differentiation. Medulloepitheliomas are malignant tumours of primitive neuro-epithelium usually involving the cerebral hemispheres. This report demonstrates their possible extraspinal presacral occurrence. By immunohistochemistry, neuron-specific-enolase, S100 protein, vimentin, cytokeratin and glial fibrillary acidic protein were found in some tumour cells. Electron microscopy demonstrated poorly differentiated cells forming stratified epithelium resting on a basal lamina and short junctional complexes at the apical pole. Ultrastructural evidence of ependymal differentiation was observed. Presacral medulloepithelioma may arise from undifferentiated embryonic cells forming the presacral remnants of the neurenteric canal.

Adolescent↗

PubMed1999

Busulphan is active against neuroblastoma and medulloblastoma xenografts in athymic mice at clinically achievable plasma drug concentrations.

High-dose busulphan-containing chemotherapy regimens have shown high response rates in children with relapsed or refractory neuroblastoma, Ewing's sarcoma and medulloblastoma. However, the anti-tumour activity of busulfan as a single agent remains to be defined, and this was evaluated in athymic mice bearing advanced stage subcutaneous paediatric solid tumour xenografts. Because busulphan is highly insoluble in water, the use of several vehicles for enteral and parenteral administration was first investigated in terms of pharmacokinetics and toxicity. The highest bioavailability was obtained with busulphan in DMSO administered i.p. When busulphan was suspended in carboxymethylcellulose and given orally or i.p., the bioavailability was poor. Then, in the therapeutic experiments, busulphan in DMSO was administered i.p. on days 0 and 4. At the maximum tolerated total dose (50 mg kg(-1)), busulphan induced a significant tumour growth delay, ranging from 12 to 34 days in the three neuroblastomas evaluated and in one out of three medulloblastomas. At a dose level above the maximum tolerated dose, busulphan induced complete and partial tumour regressions. Busulphan was inactive in a peripheral primitive neuroectodermal tumour (PNET) xenograft. When busulphan pharmacokinetics in mice and humans were considered, the estimated systemic exposure at the therapeutically active dose in mice (113 microg h ml(-1)) was close to the mean total systemic exposure in children receiving high-dose busulphan (102.4 microg h ml(-1)). In conclusion, busulphan displayed a significant anti-tumour activity in neuroblastoma and medulloblastoma xenografts at plasma drug concentrations which can be achieved clinically in children receiving high-dose busulphan-containing regimens.

Administration, Oral↗

PubMed2000

Supratentorial primitive neuroectodermal tumours: diffusion-weighted MRI.

We report the clinical and pathological findings of supratentorial primitive neuroectodermal tumours (PNETs). These are rare, poorly differentiated, highly malignant neoplasms occurring primarily in young individuals. They frequently show dissemination to the spinal cord and sometimes also beyond neuraxis. Preoperative radiological diagnosis is difficult, due to the nonspecific CT and MRI characteristics. Our findings indicate that diffusion-weighted imaging (DWI) can be used to show the solid portion of the tumour preoperatively and to monitor postsurgical recovery. We describe the MRI findings in three patients with histologically confirmed supratentorial PNET, focussing on the role of DWI for improving the specificity of radiological diagnosis.

Child↗

PubMed2006

Chromosome 17 abnormalities in pediatric neuroblastic tumor with abundant neuropil and true rosettes.

Although as a group, embryonal central nervous system tumors share a common background of primitive round cells, numerous distinctive histologic features allow for further subclassification. One tumor with a unique microscopic appearance is the recently described pediatric neuroblastic tumor with abundant neuropil and true rosettes (PNTANTR). We report 2 additional cases of this unusual tumor; both arose in 4-year-old children, one a midpontine tumor and the other a large cerebral lesion. The tumors contained hypercellular sheets of undifferentiated cells, broad zones of neuropil, and scattered perivascular, Homer Wright, and multilayered ependymoblastic-like rosettes. Isochromosome 17q was detected in multiple samples from one tumor, while the other tumor showed polysomy 17. No deletions of INI1 or amplifications of MYC or MYCN were detected. This report adds 2 cases to our experience of PNTANTR and is the first to demonstrate isochromosome 17q, a molecular alteration typical of medulloblastomas.

Brain↗

PubMed1998

A novel EWS-ERG rearrangement generating two hybrid mRNAs in a peripheral primitive neuroectodermal tumour (pPNET) with a t(15;22) translocation.

The occurrence of a t(15;22) translocation in a peripheral primitive neuroectodermal tumour (pPNET) has been previously reported. Molecular examination revealed the presence in tumour mRNA of two hybrid transcripts containing the 5' portion of the EWS gene fused to the 3' portion of the ERG gene. Sequence analyses indicated that both aberrant mRNAs most likely originated from the same rearrangement, which produced different hybrid isoforms due to the presence of an alternatively spliced exon in the ERG gene. To the authors' knowledge, this is the first report of the detection of two hybrid EWS-ERG mRNAs within the same tumour.

Adult↗

PubMed1996

Computed tomography and magnetic resonance imaging findings in primitive neuroectodermal tumours in adults.

Primitive neuroectodermal tumours (PNET) are highly malignant, undifferentiated supratentorial neoplasms arising from germinal matrix cells of the primitive neural tube. PNET occur primarily in young children; they are extremely rare in adults. PNET frequently seed within the central nervous system and may be multicentric at the time of diagnosis. Previous reports of the neuroradiological findings refer solely to PNET in children. We describe the computed tomography (CT) and magnetic resonance imaging (MRI) appearances in five adult patients with pathologically proven PNET. In our series, PNET were mostly seen as rather large, heterogeneous masses with cystic and necrotic areas, intratumoral haemorrhage and focal calcification. The prominent contrast enhancement on both CT and MRI scans reflects the increased vascularity of PNET.

Adult↗

PubMed2000

Subcutaneous primitive neuroectodermal tumour in the abdominal wall of a child: long-term survival after local excision.

Tumours of the peripheral primitive neuroectodermal tumour/Ewing's sarcoma (PNET/ES) family can rarely occur as primary lesions within the skin and subcutis. We present a case of subcutaneous PNET within the abdominal wall of a 33-month-old child. Histologically it was a small round cell tumour that marked strongly for CD99 and displayed ultrastructual evidence of neural differentiation. The tumour was completely excised, but due to an initial misdiagnosis no adjuvant therapy was given. Despite this, the patient is well without evidence of disease 10 years and 3 months after surgery. A review of similar cases reveals not all patients are as fortunate, suggesting combination therapy, including chemotherapy, is still the best treatment for these tumours, even when small and superficial. Our report therefore highlights the importance of recognising PNET/ES in the skin and subcutis so appropriate therapy can be administered.

12E7 Antigen↗