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Malignant peripheral neuroectodermal tumors are rare neoplasms of the head and neck. We describe a case of a teenage girl presenting with this neoplasm in the head and neck. The clinical histological and ultrastructural features are reviewed and presented, along with guidelines for the management of this highly aggressive neoplasm.
The melanotic neuroectodermal tumor of infancy (MNTI) is a rare neoplasm that is believed to be derived from cells of the neural crest. This case demonstrates a multicentric distribution of the MNTI. The possibility of a multicentric variant of benign MNTI is discussed with respect to both the present case and previously described reports. Suggestions for evaluation and surgical management are given.
Melanotic neuroectodermal tumor of childhood is a rare lesion, but its presentation appears to be quite characteristic and a clinical diagnosis may be made with some confidence. Although this is an extremely rapidly growing, aggressive tumor, local excision appears to be adequate for cure.
The majority of Ewing sarcomas and peripheral neuroectodermal tumors (PNET) that have been karyotyped contain a specific translocation, t(11;22)(q23;q11). We report here a second nonrandom translocation, der(16)t(1;16)(q21;q13), in 2 of 20 cases of Ewing sarcoma (seven previously unreported) and 2 of 7 cases of PNET (all previously unreported). All cases with this translocation also contained the t(11;22). Comparison of C-banding patterns in tumor and peripheral lymphocyte karyotypes in one case indicated that the likely breakpoints were 1q21 and 16q13. The presence of this translocation in cell lines will enable further investigation of the molecular events important in the pathogenesis of Ewing sarcoma and PNET.
Primitive neuroectodermal tumors are found in the cerebrum of children and young adults. The are clinically highly malignant and have rapid course from diagnosis to death. Their microscopic pathology reveals 90% to 95% nondifferentiation, frequent mitoses, and small dark cells with no observable cytoplasm. This paper discusses the treatment of three children with this tumor with a combination of surgery irradiation, and combination chemotherapy. The results of this approach are compared with previous reports in the literature. The average survival in this series is 24 months versus approximately 8 months reported in the literature.
Pediatric primitive neuroectodermal tumor (PNET) is a malignancy of the central nervous system currently treated with surgery, radiation therapy, and chemotherapy. Despite aggressive management, tumors recur in almost one-half of all patients. Drug resistance of tumor cells may, in part, explain the poor outcome. Resistance to chemotherapeutic agents may be related to expression of the multidrug resistance gene (MDR1) and its protein product, P-glycoprotein. The role of MDR1 in 16 instances of PNET was investigated using Western blot analysis to detect the expression of P-glycoprotein, messenger ribonucleic acid (mRNA), polymerase chain reaction to detect MDR1 mRNA expression, and Southern blot analysis to assess gene amplification. Analysis of proteins extracted from 15 tumors revealed that two of the 15 patients expressed detectable levels of P-glycoprotein. Polymerase chain reaction of ribonucleic acid from 12 PNET's revealed that six of the 12 patients (four of 10 de novo tumors and both recurrent tumors) expressed MDR1 mRNA. Southern blot analysis of deoxyribonucleic acid from 16 PNET's revealed no evidence of MDR1 amplification in any tumor. This is the first report of MDR1 expression in pediatric brain tumors. These data suggest a possible role for MDR1 in de novo and acquired drug resistance in PNET's.
Supratentorial primitive neuroectodermal tumors (S-PNETs) are uncommon lesions that occur predominantly in children and are histologically identical to cerebellar medulloblastomas. Like their cerebellar counterparts, S-PNETs often show divergent differentiation along neuronal, glial, and mesenchymal lines. The relationship of S-PNETs to medulloblastoma and other embryonal neoplasms remains controversial, largely because the cell of origin and histogenesis of these lesions are incompletely understood. To clarify these issues, we examined eight S-PNETs with antibodies to bcl-2 (an antiapoptosis protooncogene that has been postulated to be a marker of neuronal differentiation) and CD99 (a glycoprotein present in most peripheral embryonal tumors). S-PNETs in eight patients (seven males and one female; age range, 2 months to 40 years) were studied. All lesions were composed predominantly of small round cells with deeply basophilic nuclei and minimal surrounding cytoplasm. Tumors in two patients demonstrated no evidence of differentiation, two tumors neuronal differentiation only, and four tumors both neuronal and glial differentiation. No tumors stained with CD99. Three tumors showed focal, strong cytoplasmic staining with bcl-2. The positive lesions included one tumor showing neuronal differentiation only and two tumors with both neuronal and astrocytic differentiation. Patients were treated with various combinations of radiation and chemotherapy; five patients died from their tumor a mean of 1.7 years after diagnosis, two patients were alive with residual disease at 3 months and 3 years, and one patient was alive without disease at 17 months. Our findings suggest that bcl-2 positivity may identify a subgroup of patients having inhibition of apoptosis as a pathogenetic mechanism; we were unable to show any definite relationship between bcl-2 staining and neuronal differentiation. Despite their morphologic similarity, supratentorial and peripheral embryonal tumors appear to be distinct pathogenetic lesions, as evidenced by their different staining patterns with CD99.
We describe a case of an occipital lobe primitive neuroectodermal tumor (PNET) in a 60-year-old man with immunocytochemical evidence of neuronal, glial, smooth muscle and adipose tissue differentiation in the primary tumor and its metastases. This is the first case of PNET of cerebrum in which adipose tissue and smooth muscle has been demonstrated. The possible cells of origin for these mesenchymal elements is discussed.
Melanotic neuroectodermal tumor of infancy (MNTI) is a rare, distinctive neoplasm containing melanin; it primarily affects the maxilla of the infants during the first year of life. Approximately 150 instances of this tumor are reported in the medical literature. Genesis of the tumor is obscure and the diagnosis is challenging for the pathologist. Two cases operated by the first author are presented, and the diagnostic features and treatment alternatives of MNTI discussed.
Supratentorial primitive neuroectodermal tumors (stPNETs) are malignant tumors. We saw within three years six children with stPNETs. In four of the six children radical resection could be achieved. All had craniospinal irradiation and chemotherapy according to the HIT-91 protocol. The two children with incomplete resection died due to tumor progression after 7 and 10 months. Two of the 4 children with complete tumor resection had local relapses 8 months after diagnosis and died after 14 and 18 months. One child had a diffuse meningeal relapse 12 months after diagnosis. Despite (high-dose) systemic chemotherapy and intraventricular mafosfamide, he died 21 months after diagnosis due to tumor although remission could be achieved. Only one child is still in remission 86 months after diagnosis.
Peripheral primitive neuroectodermal tumors (PNETs) consistently demonstrate a reciprocal translocation, t(11;22)(q24;q12). This translocation has not been found in PNETs of the central nervous system including the cerebellar medulloblastoma. We report an unusual cerebellar PNET in a 4-year-old boy in which tumor cells were surrounded by pools of Alcian blue-positive material. Tumor cells were immunoreactive for neuron-specific enolase and synaptophysin. Electron microscopy revealed well-developed rough endoplasmic reticulum, cell processes with intermediate filaments, microtubules, and dense core granules, and extracellular material reminiscent of mucopolysaccharide. Reverse transcriptase polymerase chain reaction (PCR) revealed an 11;22 translocation-specific PCR product. Clinically the tumor was a cerebellar PNET with leptomeningeal dissemination and there was no evidence to suggest that it was metastatic. Histopathology, however, was indicative of an unusual PNET that also manifested t(11;22) and was associated with an aggressive clinical course.
Ewing sarcoma/'peripheral' primitive neuroectodermal tumor (ES/pPNET) is the designation given to a family of small cell neoplasms that typically arise in bone or soft tissue and are unified by their common expression of the MIC2 antigen and specific translocations involving a gene on chromosome 22q12 [the most common being t(11;22)(q24;q12)]. ES/pPNET of intracranial origin is extraordinary. We report the case of a 6-year-old boy with a large left frontal region mass that adhered to dura and was extracerebral at surgery. Histologic study revealed a high-grade, undifferentiated-appearing neoplasm of small cell type that was negative on immunostudy for glial fibrillary acidic protein, synaptophysin, desmin, leukocyte common antigen, smooth muscle actin and epithelial membrane antigen, but positive for vimentin and neuron-specific enolase and diffusely labeled by antibody O13 (which recognizes the MIC2 gene product). RNA-based polymerase chain reaction assay confirmed the diagnosis of ES/pPNET by demonstrating fusion transcripts indicative of t(11;22) translocation. Bone scan, computerized tomography of the chest and bone marrow examination revealed no systemic tumor. The limited observations published to date suggest that primary intracranial ES/pPNET is most likely to present in childhood as a circumscribed, contrast-enhancing and dural-based extracerebral mass. It must be distinguished from a variety of small cell neoplasms, particularly PNETs of central neuroepithelial origin.
OBJECTIVE AND IMPORTANCE: Peripheral primitive neuroectodermal tumor (pPNET) is a rare type of tumor, most commonly found in the limbs of children and young adults. The authors report an extremely rare case of pPNET located at the jugular foramen whose clinical course demonstrated rapid progression. CLINICAL PRESENTATION: A 23-year-old man presented with a 2-month history of progressive hoarseness and dysphagia. The neuroradiological appearance of the lesion was a jugular foramen tumor. INTERVENTION: The patient underwent a partial resection of the tumor through a far lateral suboccipital craniotomy. After surgery, the patient experienced an unexpected deterioration in consciousness. Magnetic resonance images on postoperative Day 18 revealed rapid and large expansion of the residual tumor into the posterior fossa. No adjuvant therapy was administered, and the patient died 6 weeks after diagnosis. CONCLUSION: The pathological diagnosis of the surgical specimen was pPNET, according to the findings of hematoxylin and eosin and immunohistochemical stainings. To the best of our knowledge, this is the first reported case of pPNET at the jugular foramen.
p53 mutation has been rarely reported in cerebral primitive neuroectodermal tumors (PNET). To determine the significance of p53 mutations in the development of cerebral PNET, we studied cerebral PNET samples from 14 patients, 8 females and 6 males with a mean age of 38 years (range 10 months to 77 years) who had total or subtotal surgical resection. Histological typing of PNET with neuronal (N) and non-neuronal (NN) differentiation groups revealed 8 and 6 cases, respectively. Six (43%) of the 14 patients had p53 mutation. The p53(+) and p53(-) groups had an age range of 19-77 with a mean of 49 years and 10 months to 57 years with a mean of 30 years, respectively. p53 expression between the PNET-N and PNET-NN groups was 5 of 8 (62.5%) and 1 of 6 (16.7%), respectively. The mutations contained 3 transitions, 2 transversions and 1 frameshift; none of them occurred at the site of 'hot-spot' residues (codons 175, 248, 273). The results suggest that: (1) p53 mutation in cerebral PNET tends to show a higher incidence of neuronal differentiation and occurs in the older age group in Taiwan, (2) there was no difference in survival time between the PNET-N and PNET-NN groups (7 months and 6 months) (P = 0.54), and between p53(+) and p53(-) groups (6 months and 7 months) (P = 0.57), and (3) PNET may be an entity of a heterogenous group of tumors with different genetic mechanisms controlling their trends of differential lineage. Further studies are needed to determine the significance of p53 mutations in PNET development, especially the role of carcinogens in the genesis of PNET in Taiwan.
Two cases of primitive neuroectodermal tumor of the lung are reported. The first case is a 41-year-old man with a tumor in the left upper lung, and the second case is a 30-year-old woman with a tumor in the right lower lung. In both cases, the tumors originated in the lung but not in the chest wall. No distant metastasis was detected. In case 1, transcutaneous fine-needle biopsy (TCNB) revealed small round cell proliferation, although bronchoscopic examination showed no abnormal findings. Both the expression of Mic2 protein and t(11;22)(q24;q12) translocation were proved in the tumor cells. The tumor cells were positive for periodic acid-Schiff (PAS), neuron-specific enolase (NSE), and vimentin, but negative for Leu7, chromogranin A, and pro-gastrin-releasing peptide (ProGRP). In case 2, bronchoscopic examination showed only compressive change in right lower lobe bronchi. TCNB revealed small round tumor cells expressing Mic2 protein. The tumor cells were negative for leukocyte common antigen, S100 protein, pankeratin, chromogranin A, and desmin, but weakly positive for NSE and moderately positive for Ki-67 (MIB1). Both patients were successfully treated by the combination of surgical resection and chemotherapy, and are alive with no sign of recurrence for approximately 22 months in case 1 and 16 months in case 2.
Supratentorial primitive neuroectodermal tumors (S-PNETs), which have also been called cerebral neuroblastomas, have been considered to be the hemispheric equivalent of posterior fossa medulloblastomas. Twenty-seven children with S-PNETs (excluding pineoblastomas) which were confirmed by central pathology review were treated on the CCG-921 protocol from 1986 to 1992. After operation, all patients were staged with CSF cytology and spinal myelography or magnetic resonance scans and were treated with craniospinal irradiation and chemotherapy. Data from these 27 patients have been reviewed to evaluate neurosurgical treatment, survival, and prognostic variables that correlate with survival. Overall survival at 5 years was 34% (SE 20%) and progression-free survival (PFS) was 31% (SE 18%), which is lower than the survival of patients with posterior fossa PNETs (medulloblastomas). PFS was significantly worse in children 1.5-3 years of age at diagnosis and in those with evidence of tumor dissemination at the time of diagnosis. Large preoperative tumors were more likely to be associated with greater than 1.5 cm2 residual tumor postoperatively. Neurosurgeons estimated that less than 1.5 cm2 of residual tumor was present in 52% of the cases; postoperative scans confirmed that in 58%. For children with less than 1.5 cm2 residual tumor, postoperative survival at 4.0 years was 40% (SE 22%); for those with greater than 1.5 cm2 residual tumor, survival was 13% (SE 8%). The difference did not reach statistical significance, due to small numbers in this series, though a trend did exist (p = 0.19). Large series will be required to clarify the effects of extent of resection on survival.
An 8-month-old baby girl with a supratentorial primitive neuroectodermal tumor showed an unusual aberration involving the short arm of chromosome 11. Seven abnormal metaphase cells had 49 chromosomes with trisomies of chromosomes 9 and 13, and partial trisomies of 1q and 18p. One homologue chromosome 11 was strikingly abnormal showing a long acrocentric-like form, which was composed of the long arm of chromosome 1 and an addition to the short arm of chromosome 11. This was characterized by fluorescence in situ hybridization using a partial arm chromosome-painting probe.
OBJECTIVE: To improve the diagnosis and treatment of primitive neuroectodermal tumors (PNET) of the pancreas. METHODS: One patient with PNET of the pancreas was reported in this article. The corresponding literatures on the diagnosis and treatment was reviewed. RESULTS: The patient was diagnosed as pancreatic PNET by her clinical, microscopic, and immunohistochemical features as well as cytogenetic analysis after the resection of the tumor located in the uncinate process in PUMC Hospital. Radiochemotherapy was given after the operation for 8 months and no recurrence was observed. Since PNET of pancreas have no specific clinical symptoms and most patients have jaundice and/or abdominal pain, the diagnosis depended on the immunohistochemical features of positive P30/32(MIC2) and at least two of the neural markers. The cytogenetic analysis showed translocation mainly harbored the characteristic t (11; 22) (q24; q12). Since pancreatic PNET were highly aggressive, early chemotherapy, close follow-up, and immediate surgical interventions were required as early as possible. CONCLUSION: PNET can occur in pancreas, and diagnosis and treatment should be made as early as possible to improve the outcome.