1/18. trisomy of the long arm of chromosome 1 resulting in a dicentric derivative (6)t(1;6) chromosome in a child with myelodysplastic syndrome following treatment for a primitive neuroectodermal tumor.We report the clinical, hematologic, and cytogenetic findings for a child with secondary myelodysplastic syndrome (MDS) after treatment for a primitive neuroectodermal tumor. At the time of conversion to MDS, conventional cytogenetics revealed an unbalanced der(6)t(1;6) that resulted in trisomy of the long arm of chromosome 1 and partial monosomy and duplication of 6p. Using alpha satellite probes, fluorescence in situ hybridization of bone marrow cells showed that the rearranged chromosome contained the centromeres of both chromosomes 1 and 6, thus forming a dic(1;6) resulting in trisomy 1q. This report is the first to describe a case of childhood secondary myelodysplastic syndrome associated with a trisomy 1q involving chromosome 6.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/18. Primary primitive neuroectodermal tumor of the kidney.Primitive neuroectodermal tumor (PNET) is a small round cell sarcoma that mainly develops in the central nervous system and soft tissues of childhood; however recently, primary occurrence of this tumor in the kidney has been reported. We experienced one case of PNET primarily arose in the kidney without metastasis. The patient was a 28-year-old man whose chief complaint was abdominal pain, especially on exercise. On computed tomography scan and magnetic resonance imaging, a solid lesion was found in the left kidney, and a left nephrectomy was performed based on the diagnosis of a tumor in the left kidney. The tumor was within the parenchyma of lower end of left kidney protruding into the abdominal cavity. Histologically, diffuse proliferation of primitive small round cells with rosette formation was found. Immunohistochemically, MIC2 gene product, neuron-specific enolase and S-100 protein were positive. No metastasis to the regional lymph nodes was found. From these observations, the tumor was diagnosed as PNET primarily arising in the left kidney. Although chromosome analysis was not performed, EWS-FLI1 chimera gene was identified by reverse transcriptase-polymerase chain reaction on the freshly frozen specimen and fluorescence in situ hybridization on paraffin sections.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
3/18. PNET-like features of synovial sarcoma of the lung: a pitfall in the cytologic diagnosis of soft-tissue tumors.Fine-needle aspiration (FNA) cytology of soft-tissue tumors is evolving. As more experience is gained, we are becoming aware of potential pitfalls. We describe 2 cases of synovial sarcoma of the lung, primary and metastatic, in patients who had FNA biopsy performed on a lung mass. The cytologic smears showed extremely cellular groups of malignant small round cells, intersected by small blood vessels, with numerous loose single cells, in a background of macrophages and mature lymphocytes. The tumors displayed monomorphic cells forming rosettes and displaying occasional mitoses. A diagnosis of neuroendocrine tumor/primitive neuroepithelial tumor (PNET) was suspected. Furthermore, this suspicion was supported by immunohistochemical stains, which showed positivity for a neuroendocrine marker, Leu 7 (case 1), and for a neural marker, CD 99 (O 13 or HBA 71) (both cases); and negativity for cytokeratins (case 1). The resection specimen of case 1 had mostly tightly packed small round cells, with occasional rosettes, similar to the FNA biopsy, and focal areas composed of spindle cells, organized in a focal fibrosarcoma-like and hemangiopericytoma-like pattern. A balanced translocation between chromosomes X and 18, demonstrated by both karyotyping and fluorescent in situ hybridization (FISH), enabled us to make a diagnosis of synovial sarcoma, which was histologically classified as poorly differentiated. Case 2 was a metastatic biphasic synovial sarcoma of the arm, with a prominent epithelial component. Synovial sarcoma, when composed mainly of small round cells on cytologic smears, is a great mimicker of neuroendocrine/PNET tumors, with light microscopic and immunohistochemical overlap. awareness of this potential pitfall may aid in preventing a misdiagnosis. Its recognition is of major concern, especially for the poorly differentiated variant, because it is associated with a worse prognosis.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
4/18. Cytogenetic and histopathologic studies of congenital supratentorial primitive neuroectodermal tumors: a case report.Primitive neuroectodermal tumors (PNET) represent about 25% of primary central nervous system tumors in childhood, but congenital PNETs are rare. Cytogenetic studies and studies on molecular pathology have identified several genetic alterations in medulloblastoma, but molecular investigations on supratentorial PNETs are infrequent. We present a male newborn with a large congenital PNET of the right cerebral hemisphere and the molecular analysis of the tumor. Tumor tissue was investigated by routine histology and immunohistochemistry. fluorescence in-situ hybridization was carried out on native tumor tissue to investigate deletions on chromosome 17p and to analyze c-Myc or N-Myc amplifications. Histologic examination revealed a primitive neuroectodermal tumor with massive extension covering almost the entire right hemisphere. Genetic analysis of the native tumor tissue of our patient excluded a deletion of chromosome 17p. An amplification of the c-Myc or N-Myc oncogene was absent using fluorescence in-situ hybridization. Despite unremarkable genetic analysis in our case prognosis was poor, suggesting that there are additional, yet unknown constitutional genetic aberrations in the pathogenesis of congenital supratentorial PNET.- - - - - - - - - - ranking = 2keywords = hybridization (Clic here for more details about this article) |
5/18. Atypical pleomorphic extraosseous ewing tumor/peripheral primitive neuroectodermal tumor with unusual phenotypic/genotypic profile.A pleomorphic undifferentiated tumor primarily located in the retroperitoneum with a phenotype compatible with an extraosseous Ewing tumor/peripheral primitive neuroectodermal tumor (ET/pPNET) pattern and unusual molecular features is described. Immunohistochemically, HBA-71 (CD99/mic2) and several neural markers were intensively expressed together with scattered cells expressing carcinoembryonic antigen (CEA). Short-term culture showed biphasic neuroblastic and epithelioid cell populations, with the latter expressing germ cell markers (CEA, alpha-fetoprotein, and the beta-subunit of chorionic gonadotrophin). Conventional cytogenetics displayed several chromosomic rearrangements, especially a complex translocation t(17,2,22,13) (q21::q11-->q33::q12-->q13::q14). These structural abnormalities were confirmed using fluorescence in situ hybridization analysis. Molecular studies revealed EWS-FEV fusion transcripts (exon 7 of the EWS gene and exon 2 of the FEV gene). In addition, a new p53 mutation not previously reported in ET/pPNET involving exon 5 codon 138: GCC to GAC (Ala/Asp) was detected.In our case, we emphasize the presence of atypical features not only from the phenotypic point of view but also at the genetic level as well as the value of detecting such markers in the differential diagnosis with other abdominal pleomorphic tumors.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
6/18. Unusual aberration involving the short arm of chromosome 11 in an 8-month-old patient with a supratentorial primitive neuroectodermal tumor.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.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
7/18. 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.- - - - - - - - - - ranking = 5keywords = hybridization (Clic here for more details about this article) |
8/18. Cytokeratin-positive meningeal peripheral PNET/Ewing's sarcoma of the cervical spinal cord: diagnostic value of genetic analysis.Peripheral primitive neuroectodermal tumor (PNET)/Ewing's sarcoma (ES) of the central nervous system is extremely rare and should be differentiated from central PNET and other small blue round cell tumors. We describe a case of a meningeal peripheral PNET/ES of the spinal cord in an 11-year-old boy. Immunohistochemically, the small blue round cell tumor showed expression of epithelial markers and of CD99, thus posing an important differential diagnostic problem with a poorly differentiated synovial sarcoma. fluorescence in situ hybridization revealed rearrangement of the EWS gene, as seen in peripheral PNET/ES. Peripheral PNET/ES does occur in the central nervous system, but its diagnosis can be extremely difficult on morphologic and immunohistochemical grounds alone. Genetic analysis plays a key role in its distinction from other small blue round cell tumors.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
9/18. Intracranial Ewing sarcoma.The occurrence of primary extraosseous Ewing sarcoma (EES) of the central nervous system (CNS) has only rarely been reported in the literature. It is important to distinguish this entity from the more common central primitive neuroectodermal tumor (PNET) of brain, since the management of these tumors is different from that of EES. We present the clinical, radiologic, and pathologic features of two cases of EES occurring in the brain. The diagnosis was further confirmed by detection of a rearrangement of the FLI1 and/or EWS gene loci in tumors from both patients using fluorescent in situ hybridization (FISH). Although rare, the possibility of EES should be considered particularly when tumors that arise near the meningeal surface of the brain and have the pathologic appearance of a PNET. Demonstration of t(11;22)(q24;q12) by molecular analysis essentially confirms the diagnosis and enables the oncologist to choose appropriate therapy.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
10/18. Molecular cytogenetic characterization of an ins(4;X) occurring as the sole abnormality in an aggressive, poorly differentiated soft tissue sarcoma.Cytogenetic and fluorescence in situ hybridization (FISH) analysis of an aggressive undifferentiated soft tissue sarcoma diagnosed as primitive neuroectodermal tumor (PNET) revealed an insertion ins(4;X)(q31-32;p11p22) as the sole aberration. To identify the molecular genetic consequences, contigs of bacterial artificial chromosomes (BACs) covering Xp11-p22 and 4q31-32 were constructed. The breakpoint in Xp22 was considered unlikely to be of pathogenetic significance, as it was very close to the Xp telomere, a region devoid of known or predicted genes. The breakpoint in Xp11 was mapped within a BAC clone containing BCOR, encoding a BCL6 (B-cell lymphoma 6)-interacting protein that may influence apoptosis, as the only known gene. FISH analysis with three overlapping clones on normal chromosomes 4 disclosed that the insertion of Xp11 material in der(4) was accompanied by a deletion of chromosome 4 material. Only a predicted gene (XM_094074) was shown to be partially included in the deletion. This gene displays a high similarity with the gene encoding the embryonic blastocoelar extracellular matrix (ECM) protein in sea urchin, which is involved in the migration of the primary mesenchyme cells during embryogenesis. Our results suggest that BCOR and/or an ECM-like protein could be involved in the pathogenesis of a subgroup of PNET or PNET-like sarcomas.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
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