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PubMed2002

Fine needle aspiration cytology in the diagnosis and management of children and adolescents with Ewing sarcoma and peripheral primitive neuroectodermal tumor.

PURPOSE: The utility of fine needle aspiration cytology (FNAC) in conjunction with immunocytochemistry in the diagnosis of Ewing sarcoma and peripheral primitive neuroectodermal tumor, the Ewing family of tumors (EFT), is retrospectively described. PATIENTS AND METHODS: During a 10-year period 24 children and adolescents were diagnosed at Karolinska Hospital to have EFT of bone or soft tissue using FNAC. Criteria for diagnosis was based on cytomorphology combined with immunocytochemistry. The median age was 14.1 years (range 0.7-20.2). FNAC was performed within a median time of 1 day after referral. RESULTS: Forty aspiration procedures were performed, 24 at primary work up in 23 patients and 16 at suspected relapses in 10 patients. A primary cytologic diagnosis of EFT was obtained in 22 of 23 cases. In nine cases with primary disease there was no histologic confirmation. Two tumors were on FNAC diagnosed as neuroblastoma versus EFT, and EFT, respectively. Histopathology on resected tumor tissue from these patients showed EFT and small cell osteosarcoma, respectively. Suspected relapse was found to be positive at five and negative at 11 occasions. Immunocytochemistry was positive for CD45 (LCA) in 0/12, for desmin in 2/21, for MIC2 in 15/15, for NB84 in 1/3, for NFP in 7/7, for NSE in 12/18, for S-100 in 4/11 and for vimentin in 18/19. CONCLUSIONS: The results show that FNAC together with immunocytochemistry is a rapid, physically atraumatic and accurate method in diagnosing both primary EFT of bone and soft tissue as well as relapses.

Adolescent↗
PubMed1997

Long-term survival in an adult metastatic renal peripheral primitive neuroectodermal tumor (PPNET) with multimodality treatment including high-dose chemotherapy.

We describe a 42-year-old male patient with a primitive peripheral neuroectodermal tumor (PPNET) arising from the kidney. The patient was treated sequentially with surgery, radiotherapy, experimental cytokine treatment (rhIL-6), combination chemotherapy and consolidated in complete remission with high-dose chemotherapy, supported by autologous stem cells (AST) and hematopoietic growth factors. The patient remains in complete remission at 34+ months after AST and is surviving disease-free for five years after initial presentation. The case presented here is unusual because of the renal origin and the long remission duration and survival when compared with the usual outcome of adult metastatic PPNET. High-dose chemotherapy may have favorably influenced the outcome in this patient. The case is discussed in the context of the general treatment of metastatic PPNET.

Adult↗
PubMed1994

EWS-erg and EWS-Fli1 fusion transcripts in Ewing's sarcoma and primitive neuroectodermal tumors with variant translocations.

We have determined the frequency of EWS fusion transcripts in a series of primary Ewing's sarcomas and peripheral primitive neuroectodermal tumors and cells lines. Type 1 and 2 EWS-Fli1 fusions were demonstrated in 8 cell lines and 14 patient samples. Five patients with cytogenetically characterized rearrangements of chromosome 22 that did not involve chromosome 11 were included in these studies. A novel EWS-Fli1 in-frame isoform fusing EWS to exon 8 of Fli1 was isolated from a tumor with a variant t(12;22;22)(q14;p1;q12) translocation. Three in-frame isoforms of a novel hybrid transcript derived from the fusion of EWS with the ETS domain of the human erg gene were identified in patient samples and a cell line with cytogenetically unidentified or cryptic translocations involving chromosomes 21 and 22. Interphase analysis by fluorescent in situ suppression hybridization using two overlapping erg yeast artificial chromosome clones demonstrated disruption of the erg gene on chromosome 21 in a patient sample with monosomy 22. Our results provide new information about the involvement of EWS in small round cell tumors involving exchange of its putative RNA-binding domain with DNA-binding domains derived from different members of the ETS family of transcription factors. These studies emphasize the utility of reverse transcriptase PCR analysis and fluorescent in situ hybridization as additional diagnostic tools for differential diagnosis among small round cell tumors.

Adolescent↗
PubMedDate not supplied

Aspiration cytology, immunocytochemistry and electron microscopy of a malignant peripheral neuroectodermal tumor. A case report.

The findings of fine needle aspiration (FNA) cytology, immunocytochemical staining and electron microscopy (EM) in a case of malignant peripheral neuroectodermal tumor (PNET) presenting as a soft tissue mass in the lateral abdominal wall are reported. The immediate evaluation of the aspirate revealed cells of a small round cell malignant tumor. To provide a specific preoperative diagnosis, additional cytologic material was aspirated for immunocytochemical and ultrastructural investigations. While the results of EM were nonspecific, allowing only the exclusion of other small round cell malignancies, immunocytochemical staining of the aspirate was suggestive of a PNET. The diagnosis of PNET was corroborated by histopathologic and immunohistochemical findings. This case indicates that an exact preoperative categorization of small round cell malignant tumors can be made by FNA biopsy in otherwise equivocal cases when immunocytochemical and ultrastructural techniques are also utilized.

Abdominal Muscles↗
PubMed2002

Pleomorphic primitive neuroectodermal tumor with glial and neuronal differentiation: clinical, pathological, cultural, and chromosomal analysis of a case.

This paper examines a case of pleomorphic primitive neuroectodermal tumor (PNET) with glial and neuronal differentiation in a 7-year-old girl who was clinicopathologically reported with immunohistochemical and chromosomal analysis. Clinically, a highly aggressive behavior leading to early recurrence with cerebrospinal fluid seedings was characteristic despite total removal and chemoradiation therapy. Pathologically, severe pleomorphism was noted and large ganglioid cells were predominant. Immunohistochemically, the expression of low-molecular neurofilament was recognized in the surgical specimens and increased in the recurrence. Coexpression of vimentin and neurofilament/GFAP was recognized in the culture. Chromosomal analysis showed near-diploidy, but different karyotype from that PNETs previously reported. These findings suggested that PNETs with pleomorphism and differentiation into both glial and neuronal lineages may show aggressiveness and require more aggressive therapy.

Brain Neoplasms↗
PubMed1998

Molecular analysis of childhood primitive neuroectodermal tumors defines markers associated with poor outcome.

PURPOSE: The diagnostic and prognostic significance of well-defined molecular markers was investigated in childhood primitive neuroectodermal tumors (PNET). MATERIALS AND METHODS: Using microsatellite analysis, Southern blot analysis, and fluorescence in situ hybridization (FISH), 30 primary tumors and six CSF metastasis specimens were analyzed for loss of heterozygosity (LOH) of chromosomes 1q31, 6q, 9q22, 10q, 11, 16q22, and 17p13.1 and/or high-level amplification of the c-myc gene. Experimental data were compared with clinical stage and outcome. RESULTS: LOH of chromosome 17p13.1 was found most frequently (14 of 30 tumors, six of six CSF metastasis specimens); LOH of chromosomes 10q, 16q22, 11, 6, 9q22, and 1q31 was observed in 20.6%, 20%, 14.3%, 12%, 10%, and 0%, respectively. Eight of 32 tumors and CSF specimens showed amplification of c-myc. All tumors with amplification of c-myc were resistant to therapy and had a fatal outcome (mean survival time, 9.3 months). Tumors that displayed LOH of chromosome 17p were associated with metastatic disease. The prognosis of these tumors was worse only when associated with amplification of c-myc. Three of three patients with LOH of 9q22 relapsed. CONCLUSION: In our study, amplification of c-myc was a poor-prognosis marker in PNET. LOH of chromosome 17p was associated with metastatic disease. Molecular analysis of primary tumors using these markers may be useful for stratification of children with PNET in future prospective studies. The other aberrations investigated were not of significant prognostic value, but may provide an entry point for future large-scale molecular studies.

Adolescent↗
PubMed2002

Primitive neuroectodermal tumor of the transverse colonic mesentery defined by the presence of EWS-FLI1 chimeric mRNA in a Japanese woman.

We report a case of primitive neuroectodermal tumor (PNET) arising in the transverse colonic mesentery. A 24-year-old Japanese woman was admitted to Kagoshima City Hospital with complaints of abdominal pain and sensations of abdominal fullness of 5 months' duration. On palpation, a mass the size of an infant's head was noted in the right flank. Abdominal computed tomography (CT) and ultrasonography showed a huge mass that consisted of multiple cystic components. On arteriography, a slight tumor stain appeared, with stretched and displaced tributaries of the right colic and middle colic arteries. Barium swallow examination demonstrated that the ascending colon was shifted to the right and small intestine to the left. We performed an en-bloc resection of the tumor in the transverse colonic mesentery, including the ascending colon, proximal jejunum (20 cm in length), and greater omentum. The resected tumor was 12 x 10 x 7 cm in size, 590g in weight, elastic soft in consistency, and multicystic. Histologically, the specimens showed a sheet-like proliferation of spindle-to-polygonal cells, and focally, the tumor formed rosette structures. Immunohistochemically, the tumor cells were positive for neuron-specific enolase (NSE) and mic-2. EWS-FLI1 chimeric mRNA was detected by reverse transcriptase-polymerase chain reaction (RT-PCR). Based on the above findings, we finally diagnosed the tumor as PNET of the colonic mesentery. There has been no recurrence for 20 months after operation. PNET arising in the mesentery is very rare, and we distinguished PNET from other tumors by immunohistochemical examination and by demonstration of the presence of EWS-FLI1 chimeric mRNA in the tumor.

Adult↗
PubMed1995

Very-high-dose short-term chemotherapy for poor-risk peripheral primitive neuroectodermal tumors, including Ewing's sarcoma, in children and young adults.

PURPOSE: To improve the prognosis of patients with poor-risk peripheral primitive neuroectodermal tumors (pPNETs; including peripheral neuroepithelioma and Ewing's sarcoma), while testing the feasibility of intensive use in adolescents and young adults of high-dose cyclophosphamide, doxorubicin, and vincristine (HD-CAV). PATIENTS AND METHODS: This report concerns previously untreated patients with newly diagnosed pPNET deemed poor-risk because of a tumor volume more than 100 cm3 or metastases to bone or bone marrow. The P6 protocol consists of seven courses of chemotherapy. Courses 1, 2, 3, and 6 include 6-hour infusions of cyclophosphamide on days 1 and 2 for a total of 4,200 mg/m2 per course (140 mg/kg per course for patients < 10 years old), plus 72-hour infusions of doxorubicin 75 mg/m2 and vincristine 2.0 mg/m2 beginning on day 1 (HD-CAV). Courses 4, 5, and 7 consist of 1-hour infusions of ifosfamide 1.8 g/m2/d and etoposide (VP-16) 100 mg/m2/d, for 5 days. Granulocyte colony-stimulating factor (G-CSF) and mesna are used. Courses start after neutrophil counts reach 500/microL and platelet counts reach 100,000/uL. Surgical resection follows course 3 and radiotherapy follows completion of all chemotherapy. RESULTS: Among the first 36 consecutive assessable patients (median age, 17 years), HD-CAV achieved excellent histopathologic or clinical responses in 34 patients and partial responses (PRs) in two patients. For 24 patients with locoregional disease, the 2-year event-free survival rate was 77%; adverse events were two locoregional relapses, one distant relapse, and one secondary leukemia. All six patients with metastatic disease limited to lungs achieved a complete response (CR) and did not relapse; one is in remission 36+ months from diagnosis, but the other patients are not assessable in terms of long-term efficacy of the P6 protocol because of short follow-up time (n = 3), additional systemic therapy (bone marrow transplantation), or septic death (autopsy showed no residual pPNET). All six patients with widespread metastases had major responses, including eradication of extensive bone marrow involvement, but distant relapses ensued. Myelosuppression was severe, but most patients received the first three courses of HD-CAV within 6 to 7 weeks. Major nonhematologic toxicities were mucositis and peripheral neuropathy. CONCLUSION: Excellent antitumor efficacy and manageable toxicity support the dose-intensive use of HD-CAV for pPNET in children, as well as in young adults. Consolidation of remissions of pPNET metastatic to bone and bone marrow remains a therapeutic challenge.

Adolescent↗
PubMed2002

Primary primitive neuroectodermal tumor of the spinal cord: case report and review of the literature.

We present the clinical, radiological, and pathological features of a primary primitive neuroectodermal tumor (PNET) that occurred in the thoracic spinal cord of a 69-year-old man. Magnetic resonance imaging (MRI) demonstrated on T1-weighted images a 2x1x5 cm isointense intraspinal mass with homogeneous contrast enhancement extending from the C7 to the Th3 level. There was no clinical or radiological evidence for the existence of an intracranial tumor. Histological examination revealed a small round cell tumor with rosette formation and immunohistochemical characteristics of a PNET. The patient is the oldest among the 20 cases with this rare spinal cord neoplasm reported so far in the literature; the previously published cases are briefly reviewed.

Age of Onset↗
PubMed2003

Ewing sarcoma/primitive neuroectodermal tumor of the chest wall: impact of initial versus delayed resection on tumor margins, survival, and use of radiation therapy.

OBJECTIVE: To establish outcome and optimal timing of local control for patients with nonmetastatic Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET) of the chest wall. METHODS: Patients < or =30 years of age with ES/PNET of the chest wall were entered in 2 consecutive protocols. Therapy included multiagent chemotherapy; local control was achieved by resection, radiotherapy, or both. We compared completeness of resection and disease-free survival in patients undergoing initial surgical resection versus those treated with neoadjuvant chemotherapy followed by resection, radiotherapy, or both. Patients with a positive surgical margin received radiotherapy. RESULTS: Ninety-eight (11.3%) of 869 patients had primary tumors of the chest wall. Median follow-up was 3.47 years and 5-year event-free survival was 56% for the chest wall lesions. Ten of 20 (50%) initial resections resulted in negative margins compared with 41 of 53 (77%) negative margins with delayed resections after chemotherapy (P = 0.043). Event-free survival did not differ by timing of surgery (P = 0.69) or type of local control (P = 0.17). Initial chemotherapy decreased the percentage of patients needing radiation therapy. Seventeen of 24 patients (70.8%) with initial surgery received radiotherapy compared with 34 of 71 patients (47.9%) who started with chemotherapy (P = 0.061). If a delayed operation was performed, excluding those patients who received only radiotherapy for local control, only 25 of 62 patients needed radiotherapy (40.3%; P = 0.016). CONCLUSION: The likelihood of complete tumor resection with a negative microscopic margin and consequent avoidance of external beam radiation and its potential complications is increased with neoadjuvant chemotherapy and delayed resection of chest wall ES/PNET.

Adult↗
PubMed2005

Patterns of treatment failure in infants with primitive neuroectodermal tumors who were treated on CCG-921: a phase III combined modality study.

PURPOSE: To analyze patterns of treatment failure in infants with primitive neuroectodermal tumors (PNETs) who were treated primarily with chemotherapy in a large multi-institutional study. MATERIALS AND METHODS: Sixty-five prospectively staged patients with PNET confirmed by central pathology review, who were 18 months or younger were treated on Children's Cancer Group Study 921 (CCG-921) primarily with chemotherapy. Forty-six patients had posterior fossa (PF) primary tumors and 19 patients had supratentorial (ST) primaries. Patterns of sites of initial treatment failure were analyzed and compared to failure patterns of 180 older children who had PF-PNETs, and 44 older children with ST-PNETs who were treated on the same protocol. RESULTS: The entire cohort of younger patients fared much worse than those older than 18 months. Cumulative 5-year relapse incidence (+/-SE) for younger patients with PF-PNETs was 64.5 +/- 8.9% for patients without metastases (M0) compared to 71.4 +/- 13.4% for patients with metastases (M+). The cumulative 5-year relapse incidences for younger patients with ST-PNETs were 64.3 +/- 13.7% for M0 patients compared to 100 +/- 33.3% for M+ patients. Relapses in these patients occurred within 2 years. The overall treatment failure rate was significantly higher for younger compared to older patients with PF-PNET and ST-PNET. There was no statistically significant difference in relapse patterns between patients with PF primary tumors and ST primaries when stratified by stage. There was no statistically significant difference in relapse patterns between M0 and M+ patients. All patients had a high risk of recurrence at primary tumor site. Younger patients who had PF primary tumors without metastasis at presentation were significantly more likely to relapse in PF than older patients. Younger patients were at significant risk of relapse in the spine, but none had it as the sole site of first relapse. CONCLUSIONS: Despite aggressive chemotherapy, younger children with PNETs have high rates of treatment failure and fare worse than high-risk, older patients with PF-PNETs, indicating the need to maximize local, regional, and systemic therapies.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1998

Missense mutations in SMOH in sporadic basal cell carcinomas of the skin and primitive neuroectodermal tumors of the central nervous system.

About one-third of sporadic basal cell carcinomas (BCCs) of the skin and 10-15% of primitive neuroectodermal tumors (PNETs) of the central nervous system show mutations in the PTCH tumor suppressor gene. The PTCH gene product (Ptch) functions as a transmembrane receptor for the Sonic hedgehog protein (Shh) and interacts with another transmembrane protein called Smoh. To further elucidate the significance of alterations in the Shh signaling pathway, we investigated 31 sporadic BCCs and 15 PNETs for the mutation and/or expression of SMOH, PTCH, SHH, and GL11. In addition, we fine-mapped the SMOH gene locus by fluorescence in situ hybridization to chromosomal band 7q32. Mutational analysis identified four BCCs with somatic missense mutations in SMOH affecting codon 535 (TGG==>TTG: Trp==>Leu) in three tumors and codon 199 (CGG==>TGG: Arg==>Trp) in one tumor. A missense mutation at codon 533 (AGC==>AAC: Ser==>Asn) was found in one PNET. PTCH mutations were detected in eight BCCs and one PNET. Two BCCs demonstrated mutations in both SMOH and PTCH. The majority of tumors showed an increased expression of SMOH, PTCH, and GL11 transcripts as compared with that of normal skin and nonneoplastic brain tissue, respectively. In contrast, only one BCC and one PNET expressed SHH mRNA at levels detectable by reverse transcription-PCR, and no SHH gene mutations were found. In summary, our results indicate that both PTCH and SMOH represent important targets for genetic alterations in sporadic BCCs and PNETs.

Adolescent↗
PubMed1997

Prognostic significance of chromosome 17p deletions in childhood primitive neuroectodermal tumors (medulloblastomas) of the central nervous system.

Deletions in the short arm of chromosome 17 (17p) are the most common genetic abnormality in primitive neuroectodermal tumors of the posterior fossa/medulloblastoma (PNET/Mb). The biological consequences of these deletions are not known for children with PNET/Mb; however, the presence of a tumor suppressor gene located in 17p, distinct from p53, has been implicated in tumorigenesis. Two recent studies suggest that 17p deletions in PNET/Mb are associated with a poor prognosis. To address this question, we identified deletions of chromosome 17p by cytogenetic and/or molecular biology methods in tumor biopsy samples from 56 patients with PNET/Mb. Associations between clinical characteristics or survival outcomes and 17p status were examined by multivariate analysis. Forty-one percent of PNET/Mb cases had a deletion of 17p. No significant association was found between 17p deletion and shorter survival duration or higher metastatic stage. Multivariate analysis did not find independent prognostic significance for 17p deletions after accounting for the effects of significant clinical variables. A larger study of the prognostic value of 17p deletion should be considered; however, clinical use of this factor to distinguish high-risk from standard-risk PNET/Mb populations is not warranted at this time.

Age Factors↗
PubMed2006

Coexistence of peripheral primitive neuroectodermal tumor and tetralogy of Fallot.

We describe a little girl with tetralogy of Fallot (TOF) who was found to have a huge peripheral primitive neuroectodermal tumor (pPNET) when she developed progressive difficulty in standing and crawling at the age of 11 months. The tumor was located in the left paraspinal region (T4-T12), with intraspinal extension causing severe compression. Nine days after surgical decompression with laminectomy, chemotherapy was initiated with alternative courses of vincristine, doxorubicin, cyclophosphamide, etoposide, and ifosfamide every 3 weeks. The muscle power in her legs recovered substantially after 2 courses of chemotherapy. Although peripheral blood for cytogenetic study revealed no chromosome abnormality, recent cytogenetic analysis has revealed a high frequency of reciprocal translocation t(11;22)(q24;q12) detected in pPNET and a strong association between TOF and chromosome 22q11 microdeletion (del 22q11). Both genetic defects involve chromosome 22q in the close region. This case report illustrates the necessity of investigating for cytogenetic change in chromosome 22 and close follow-up due to the possibility of subsequent development of malignancies in patients with TOF.

Chromosome Aberrations↗
PubMed1998

[Peripheral primitive neuroectodermal tumor in parietal pleura].

A 19-year-old woman was admitted to Kushiro city general hospital due to chest pain and dyspnea. Chest radiographs and computed tomographic scan showed a large intrathoracic mass adjacent to the pleura. Angiographs disclosed feeding veins of the tumor arising from lateral thoracic artery. Fine-needle aspiration cytology of the tumor revealed small round cells with a large nuclear/cytoplasmic ratio. Immunocytochemical study demonstrated that the tumor cells were positive for neuron-specific enolase and MIC 2 gene product. The diagnosis was primitive neuroectodermal tumor of the parietal pleura (also known as Askin tumor). Chemotherapy combined with peripheral blood stem cell transplantation reduced the size of the tumor significantly. However, multiple bone metastasis recurred, and the patient died 35 months after the start of therapy.

Adult↗
PubMedDate not supplied

Late events in pediatric patients with Ewing sarcoma/primitive neuroectodermal tumor of bone: the Dana-Farber Cancer Institute/Children's Hospital experience.

The outcome for 82 pediatric patients with Ewing sarcoma (ES) and primitive neuroectodermal tumor (PNET) of bone is reported; the patients were treated at the Dana-Farber Cancer Institute (DFCI) and Children's Hospital (CH) in Boston, MA (USA) from 1971-1988. The charts of all patients with ES/PNET of bone treated during this period were reviewed for disease status, therapy, sites of relapse, information on second malignancies, and survival status. Eighty-two patients with ES/PNET of bone treated at DFCI/CH were identified. The 10-year event-free survival (EFS) rates were 12% (95% confidence interval [CI] 0, 27%) and 38% (95% CI 26, 51%) for patients with and without metastases, respectively (P = 0.002); the overall survival (OS) rates were 17% (95% CI 1, 33%) and 48% (95% CI 35, 61%) for patients with and without metastases (P = 0.001). Median follow-up for surviving patients is 10.2 years. Primary site in the pelvis also was associated with a poor outcome for patients with no metastatic disease (P = 0.006 OS, P = 0.03 EFS). Thirty-one patients survived in first remission at least 5 years from diagnosis, and of these, five experienced relapse of original disease, and five experienced secondary malignancies. Pediatric patients treated for ES/PNET of bone remain at risk for life-threatening events into the second decade of follow-up. After 5 years, the risk of second malignant neoplasm is at least as high as the risk of late relapse. Prolonged follow-up of patients with ES and PNET of bone is indicated.

Adolescent↗
PubMed1994

Immunohistochemical detection of P-glycoprotein in Ewing's sarcoma and peripheral primitive neuroectodermal tumors before and after chemotherapy.

The authors evaluated P-glycoprotein expression in a total of 35 cases of Ewing's sarcoma and peripheral primitive neuroectodermal tumors (PNET). Fifteen cases had matched tumors before and after treatment. The 20 unmatched tumors included 14 pretreatment PNETs and Ewing's sarcomas and 6 posttreatment Ewing's sarcomas. Two antibodies, C219 and JSB-1, were used. Immunoreactivity was almost exclusively membranous. Variability in the number of positive cells and in staining intensity was noted within individual tumors. Among the 15 matched tumors, 7 were positive for P-glycoprotein before treatment; 6 of these remained positive after treatment. Four of the 8 that were negative for P-glycoprotein before treatment became positive after treatment. Of the unmatched tumors, 9 of 14 pretreatment and 3 of 6 posttreatment tumors were positive. When relapse-free survival time, based on the presence or absence of P-glycoprotein positivity in pretreatment tumor samples, was evaluated in this group, no significant difference was found (P2 = .92); however, the numbers are too small to draw definitive conclusions. The high incidence of positive primary tumors suggests that P-glycoprotein expression is probably intrinsic in Ewing's sarcoma and PNET and not necessarily induced by therapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Primitive Neuroectodermal Tumor of the Meninges: An Histological, Immunohistochemical, Ultrastructural, and Cytogenetic Study.

We report a case of primitive neuroectodermal tumor (PNET) arising from the meninges in a 30-yr-old female patient whose clinical and radiological features were consistent with meningioma. The neoplasm was composed of primitive small, round cells, growing in sheets and nests in continuity with meningeal layers. Ultrastructurally, the neoplastic cells were characterized by large and regular nuclei, primitive cytoplasm with pools of glycogen, and lack of dense core granules. The neuroectodermal nature of the tumor was confirmed by positive immunostaining for vimentin, neurofilaments, neuron specific enolase (NSE), and 013 (an antibody raised against MIC2 antigen). Further support to the diagnosis was obtained by reverse transcriptase-polymerase chain reaction (RT-PCR) detection of Chromogranin A and Secretogranin II genes. t(1 1;22) translocation was also observed by RT-PCR, a finding that was not recorded in previously described intracranial PNET. The tumor followed a malignant course, recurring and spreading to chest wall and sacroiliac region over a 10-yr period. The meningeal location enlarges the topographic spectrum of intracranial PNET, and this tumor has to be considered in the differential diagnosis with meningioma.

Journal Article↗