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11/51. radiation-induced bilateral cystic frontal lobe necroses demonstrating a fluid-blood level--case report.

    A 41-year-old male developed radiation-induced bilateral cystic frontal lobe necroses after irradiation for an olfactory neuroblastoma. Computed tomography (CT) and magnetic resonance (MR) imaging revealed the lesions, one containing a fluid-blood level on CT scans and niveau formation on MR images. It was proved to be a coagulated hematoma within the cyst at surgery. Such a fluid-blood level in a radiation-induced cyst has never been reported, although hemorrhage frequently accompanies delayed radiation necrosis. Positron emission tomography with multiple tracers may be useful in differentiating cerebral radiation necrosis from tumor recurrence, because of absence of abnormal tracer accumulation.
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ranking = 1
keywords = formation
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12/51. Two malignant peripheral primitive neuroepithelial tumor cell lines established from consecutive samples of one patient: characterization and cytogenetic analysis.

    A 6-year-old girl presented with a tumor of the right shoulder involving bone, adjacent soft tissue, and regional lymph nodes. The conventional histologic diagnosis was ambiguous, initially suggesting lymphoma. After relapse on lymphoma therapy, reevaluation with additional multiple diagnostic techniques performed on the biopsy tissue and on two cell lines derived from the biopsies established the diagnosis of a primitive neuroepithelial tumor of bone and soft tissue. This was strongly supported by 1) focal rosette formation by the tumor cells and positive immunostaining for neuron-specific enolase and synaptophysin, with absent staining for leukocyte common antigen; 2) at the ultrastructural level, formation of cellular processes containing microtubules, a paucity of neurosecretory granules, absence of synaptic junctions, formation of long "intermediate" junctions between cells, and, in culture, widespread development of rosettes; 3) marked surface positivity to W 6/32 and negativity to HSAN 1.2 antibodies; and 4) elevated expression of MYC and lack of overexpression of MYCN oncogenes. Numerical and structural abnormalities were present in the karyotype, but the expected t(11;22)(q24;q12) was not present in the tumor-involved marrow or in either of the established tumor cell lines, although there was an interstitial deletion of 11q involving breakpoints in q21 and q23.
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ranking = 16661.10706364
keywords = rosette, formation
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13/51. Primitive neuroectodermal tumor (PNET) of the urinary bladder.

    We report on the clinical, morphologic, immunohistochemical, ultrastructural, and molecular cytogenetic features of a primitive neuroectodermal tumor (PNET) primarily arising in the urinary bladder. An 81-year-old man presented with lymphedema of the lower extremities, fatigue, and urge incontinence. Radiographically, a tumor filling the entire cavity of the urinary bladder and extending into the pelvic and retroperitoneal tissue was noted. histology of tumor biopsies showed a highly cellular, focally necrotic small round-cell tumor with numerous mitoses and occasional rosette-like structures. The tumor cells displayed significant immunoreactivity for neuron-specific enolase (NSE) and the MIC2 gene product (CD99). Dense-core granules were detectable by electron microscopy. A molecular cytogenetic analysis using comparative genomic hybridization (CGH) revealed gains of the chromosomes 3p, 6, 8q, 12, 17q, and 21q. The patient died two weeks after diagnosis. To the best of our knowledge, this is the fifth reported case of a PNET of the urinary bladder, and the first that includes a molecular cytogenetic analysis based on CGH.
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ranking = 8329.05353182
keywords = rosette
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14/51. Neuroepithelial adenocarcinoma of the eye.

    A 29-year-old male patient with a microphthalmos on the right side since birth was seen in June 1987 in the University eye Clinic because of a massive exophthalmus of the former microphthalmic eye. Computer tomography revealed a diffuse, infiltrating tumor of the right orbit. The bulbus was not demarcated, and the whole orbita had to be eviscerated. Histologically, we found a solid, undifferentiated tumor with clear signs of malignancy. It consisted of epithelial cells, partly in nest formation, which were keratin positive and vimentin negative, and of more spindle-shaped formations which were keratin negative and vimentin positive. In some areas, the tumor showed a tubular or an adenoid proliferation. CEA or S-100 could not be demonstrated. The histopathological diagnosis was neuroepithelial adenocarcinoma of the eye. The differential diagnosis and the genesis of the tumor are discussed.
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keywords = formation
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15/51. Primary Ewing's sarcoma-primitive neuroectodermal tumor of the vagina.

    BACKGROUND: Only three cases of Ewing's sarcoma-primitive neuroectodermal tumor (ES-PNET) occurring in the vagina have been previously reported. CASE: A 30-year-old Chinese woman presented with a vaginal mass measuring 5 cm in greatest dimension. The tumor was composed of solid sheets of undifferentiated small round cells with numerous Homer-Wright rosettes. Immunohistochemically, it was positive for CD99, FlI-1 protein, synaptophysin, neuron-specific enolase, vimentin, and S-100 protein. The patient underwent wide local excision of the tumor and subsequent total abdominal hysterectomy with postoperative chemotherapy and radiotherapy. She is disease-free 36 months after the initial surgery. CONCLUSION: This is a rare case of ES-PNET occurring in the vagina and the first showing many distinctive Homer-Wright rosettes. A review of literature indicates that vaginal or vulvar ES-PNET affects younger women, and it may have a relatively favorable outcome.
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ranking = 16658.10706364
keywords = rosette
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16/51. Primary primitive neuroectodermal tumor (PNET) of the kidney with venous thrombus.

    Primitive neuroectodermal tumors of the kidney are rare, the diagnosis usually being made at histopathology. A young adult presented with a painful left renal mass. CT Scan of the abdomen revealed a large necrotic tumor of the left kidney. At surgery the patient was found to have a venous thrombus confined to the renal vein. Radical nephrectomy was done. Histopathology showed a round cell neoplasm with typical Homer Wright rosette formation and positive staining for neuron specific enolase (NSE) and MIC-2 on immunohistochemistry. The patient is undergoing multidrug chemotherapy and is alive and well at a follow up of nine months.
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ranking = 8330.05353182
keywords = rosette, formation
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17/51. 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.
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ranking = 8329.05353182
keywords = rosette
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18/51. Keratin-positive Ewing's sarcoma: an ultrastructural study of 12 cases.

    Ewing's sarcoma/primitive neuroectodermal tumor (EWS/PNET) is an aggressive neoplasm of bone and soft tissue. Histologically, it is characterized by the presence of small round blue cells, which usually express MIC-2 and FLI-1 immunohistochemically. The most specific feature for diagnosis, however, is cytogenetic or molecular evidence of a consistent abnormality, the t(11;22)(q24;q12), or variants thereof. The immunohistochemical expression of keratins in a significant proportion of these cases has been highlighted in several recent studies. The ultrastructural features of these keratin-positive tumors have not, however, been characterized in detail. In this study we analyzed the ultrastructural features of 12 well-documented EWS/PNETs that stained strongly for pankeratin by immunohistochemistry. Ultrastructurally, the tumor cells contained a few organelles, which included a small number of mitochondria, poorly developed Golgi complexes, free ribosomes, and inconspicuous rough-endoplasmic reticulum. Rudimentary cell junctions were seen in 2 tumors while prominent junctions were observed in the remaining 10. Five tumors contained intracytoplasmic filaments, and definite tonofibrils were identified in 2. Well-developed basal lamina around tumor cells were also demonstrated in 2 tumors. Follow-up information was available for all cases. Seven patients died of disease, 2 are alive with disease, and 3 have no current evidence of disease. The cohort includes 5 patients with a type-1 translocation, which has been associated with a better prognosis in some studies; 4 of these patients have died of their disease, and 1 is alive with recurrent disease. This study shows that keratin-positive EWS/PNETs have evidence of epithelial differentiation ultrastructurally, and may possibly represent a more aggressive subset of the EWS/PNET group of tumors.
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ranking = 1
keywords = formation
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19/51. desmin positivity in primitive neuroectodermal tumors of childhood.

    In this report, we describe two rosette-forming primitive neuroectodermal tumors that were found to contain desmin by both immunohistochemistry and Western blotting. Electron microscopy on both cases was consistent with primitive neuroectodermal tumors and revealed that the tumor cells contained cytoplasmic bundles of intermediate filaments. In both cases, studies for MyoD1 protein using immunohistochemistry and Western blotting were negative. Thus, the detection of desmin in a pediatric neoplasm does not absolutely exclude the diagnosis of primitive neuroectodermal tumor and should not be considered as prima facie evidence that a small-cell tumor is a rhabdomyosarcoma.
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ranking = 8329.05353182
keywords = rosette
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20/51. Primitive neuroectodermal tumor arising in the colon: report of a case.

    Peripheral primitive neuroectodermal tumors (pPNETs) are usually found in the soft tissue of the extremities, paravertebral region, and chest wall. We report a rare case of a pPNET arising in the colon. A 59-year-old man underwent left hemicolectomy for an infiltrative ulcerating tumor, 11 cm long, in the descending colon. Histological examination of the resected specimen revealed small, round cell proliferation with rosette-like structures, and confirmed regional lymph node involvement and peritoneal dissemination near the primary tumor. Immunohistochemically, the tumor cells were positive for synaptophysin and MIC2 (CD 99). ESW-FLI1 chimeric mRNA was detected in the tumor by reverse transcriptase-polymerase chain reaction. The patient underwent resection of recurrence in the retroperitoneum 3 months later, but metastasis rapidly developed and he died of the disease 7 months after his first operation.
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ranking = 8329.05353182
keywords = rosette
(Clic here for more details about this article)
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