Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Primary malignant neuroepithelial tumors of the kidney (NETKs) comprise a group of primitive, highly malignant neoplasms that histologically and clinically are not well characterized. A large cohort of 146 of these tumors, occurring in adults and children, has been collected at a single depository site, the National Wilms' Tumor Study Group (NWTSG) Pathology Center. The authors undertook a systematic retrospective review of the histologic, ultrastructural, and clinical features of these tumors, based on materials collected by the NWTSG and the consultation files of one of the authors (J.B.B.). Histologic features were generally those of primitive neural tumors with varying amounts of rosettes and neuropil; however, a large proportion of cases displayed unusual features such as spindle cells, ganglion cells, clear cell sarcoma-like foci, rhabdoid cells, epithelioid cells, and organoid foci. CD99 staining had been performed on 69 cases and showed membranous staining in 65. The NETKs were present in patients with a wide age spectrum, ranging from 1 month to 72 years (median, 18 years). EWS/FLI1 fusion analysis using reverse transcriptase-polymerase chain reaction and immunohistochemical stains for cytokeratin, chromogranin, and epithelial membrane antigen were performed successfully on a subset of 45 cases with available paraffin blocks. Only 13 of the 45 were fusion-positive, and there was no correlation between fusion status and histology, presence of rosettes, ultrastructural features, or cytokeratin positivity. CD99-negative cases were usually fusion-negative (six of seven cases), and all three chromogranin-positive cases were fusion-negative. Tumor staging, performed on 72 clearly defined and quantifiable cases by using NWTSG criteria, indicated that these are aggressive tumors, because only six were Stage 1, compared with 16 Stage 2, 31 Stage 3, and 19 Stage 4 lesions. The authors conclude that NETKs are a somewhat diverse group of generally aggressive, high-grade lesions that may present in a wide age range and are difficult to characterize without immunohistochemistry and cytogenetics/molecular biology.
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PMID:Primary malignant neuroepithelial tumors of the kidney: a clinicopathologic analysis of 146 adult and pediatric cases from the National Wilms' Tumor Study Group Pathology Center. 1117 62

Extraskeletal Ewing's sarcoma is a rare tumor. The most common sites of occurrence are on the trunk, extremities, and retroperitoneum. This type of tumor is well characterized by recurrent chromosomal translocation such as t (11;22) (q24;q12) (EWSR1/FLI1) or t (21;22) (q22;q12) (EWSR1/ERG) and overexpression of MIC2/CD99 on tumor cell membrane. We describe the first reported case of an esophageal extraskeletal Ewing's sarcoma with confirmation from immunohistochemical and molecular diagnoses. A 56-year-old man developed a polypoid tumor located in the lower part of the esophagus. The tumor was composed of small-sized round cells showing prominent fibrillar cytoplasmic processes. Intracytoplasmic glycogen was detected in all the tumor cells. Immunoreactivity for MIC2/CD99 was positive on the membrane of all tumor cells. A reverse transcriptase-polymerase chain reaction followed by sequencing revealed an EWSR1/ERG chimeric transcript, which combined EWSR1 exon 10 with ERG exon 6. The present report added a new entity of esophageal small round cell tumor.
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PMID:Esophageal extraskeletal Ewing's sarcoma. 1182 84

We describe two cases of peripheral primitive neuroectodermal tumor-Ewing's sarcoma (PNET-ES) arising intracranially in the leptomeninges. Both tumors exhibited a primitive undifferentiated round-cell morphology. Immunohistochemical stains revealed strong membrane expression of CD99 in both cases. A t(11;22)(q24;q12) could be demonstrated with reverse transcriptase-polymerase chain reaction in one case, whereas fluorescence in situ hybridization analysis performed in the second case showed a rearrangement of the EWS gene. The occurrence of PNET-ES at this site is very unusual. Immunophenotypical as well as genetic analysis play a key role in the diagnosis and the distinction from central PNET.
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PMID:Primary peripheral PNET/Ewing's sarcoma of the dura: a clinicopathologic entity distinct from central PNET. 1206 82

Rhabdomyosarcomas (RMSs) are classified into embryonal (ERMS), alveolar (ARMS), and pleomorphic (PRMS) subtypes. ERMS, including botryoid variants, typically occurs in young children, ARMS typically occurs in older children and young adults, and PRMS occurs in older adults. Although ARMSs show thin fibrous bands separating nests of cells, abundant extracellular matrix production is rare in RMS. In the course of reviewing hyalinizing sarcomas we discovered a distinctive RMS in adults that closely mimicked osteosarcoma or chondrosarcoma because of the extensive matrix production. Four RMSs with hyalinized matrix were retrieved from our files. These cases were evaluated with respect to patient age and sex, tumor site and size, growth pattern, nuclear grade, cellularity, mitotic figures/20 high power fields, vascular invasion, necrosis, the presence of rhabdomyoblasts, multinucleated cells, and alveolar growth pattern. Immunohistochemistry for desmin, myogenin, MyoD1, actin, cytokeratin, S-100 protein, collagen II, and CD99 was performed. Reverse transcriptase polymerase chain reaction for the ARMS-associated PAX3/FKHR and PAX7/PKHF was also performed on three cases. The cases involved the forearm, hand, orbit, and nasopharynx of a 40-year-old woman, a 50-year-old man, an 18-year-old man, and a 21-year-old man, respectively. The tumors ranged from 3.7 to 8 cm and consisted of lobules and infiltrating cords of small round malignant cells embedded in a densely hyalinized matrix having both a chondroid and osteoid-like appearance. No definite lacunae or matrix calcification was present. An alveolar pattern was only present focally, and tumor giant cells were not present. One case had a single focus of rhabdomyoblastic differentiation with strap cells. Mitotic activity was >20 mitotic figures/20 high power fields in three of four cases. Immunohistochemically, one case strongly expressed desmin, whereas three cases expressed it focally, with a dot-like pattern. Myogenin was only focally positive, but MyoD1 was present in nearly every cell of each case. Two cases expressed actin and one expressed CD99. No case expressed cytokeratin, S-100 protein, or collagen II. Only one case contained adequate RNA for reverse transcriptase polymerase chain reaction, and this case was negative for the ARMS-associated gene fusions. Follow-up showed one patient to be dead of metastatic disease at 60 months despite intensive therapy, another patient to be disease free at 26 months, and the third patient to be disease free at 5 months. The fourth case is recent. These cases are a distinctive-appearing rhabdomyosarcoma easily mistaken for variants of chondrosarcoma, osteosarcoma, or even sclerosing epithelioid fibrosarcoma because of their hyalinizing appearance compounded by their typically focal and dot-like desmin expression. These four cases are essentially identical to the three unusual RMSs recently reported by Mentzel and Katenkamp as "sclerosing, pseudovascular rhabdomyosarcoma in adults." Although the focal alveolar architecture and the primitive cytologic appearance of these hyalinizing RMS suggest a relationship with ARMS, the presence of abundant strap cells in one case, the predominant expression of MyoD1 rather than myogenin, and the absence of ARMS-associated fusions genes point more strongly toward a variant of ERMS. However, the late adult age in two cases is unusual for both EMRS and ARMS, suggesting that sclerosing RMS may prove to be a distinct subtype of RMS. Study of additional cases will be necessary to more fully elucidate its place among RMS and its prognostic significance.
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PMID:Sclerosing rhabdomyosarcoma in adults: report of four cases of a hyalinizing, matrix-rich variant of rhabdomyosarcoma that may be confused with osteosarcoma, chondrosarcoma, or angiosarcoma. 1221 74

We report 2 primary renal synovial sarcoma. These tumors were formerly designated as embryonal cystic sarcoma of the kidney. Most cases are diagnosed between the ages of 20 and 50 years. Some cases show local recurrence after nephrectomy. On gross examination, tumors are large, partially necrotic, and usually contain cysts. Microscopically, tumors are characterized by monomorphic plump spindle cells. The cysts are lined by mitotically inactive epithelial cells without striking cellular atypia. The spindle cells were immunoreactive for EMA, CD56, and sometimes for CD99. They were non-reactive for desmin, actin, S 100, and cytokeratins. The cyst epithelium is cytokeratin positive. The presence of a SYT-SSX gene fusion resulting from the t(X;18) characteristic for synovial sarcoma was demonstrated by reverse transcriptase polymerase chain reaction in both tumors. Primary renal synovial sarcoma is a distinctive tumor entity, which should be considered in renal tumors consisting of spindle cells.
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PMID:[Primary renal synovial sarcoma. A new entity in the morphological spectrum of spindle cell renal tumors]. 1460 53

We report 3 cases of synovial sarcoma with rhabdoid features, initially diagnosed as adult rhabdoid tumors. Two women (case nos. 1 and 2, 35 years and 27 years of age, respectively) and one man (case no. 3, 26 years of age) presented to their physicians with right flank pain. On physical examination, a poorly defined, firm, palpable mass was found in the upper right quadrant of the abdomen in all cases. Sonography and computed tomography revealed solid, cystic masses in the right kidneys that ranged in size from 8.5 to 20.0 cm. Right radical nephrectomies were performed in all patients. One patient died of disease, and the other two patients were alive and disease-free after chemotherapy and radiotherapy. Microscopic examination revealed that the tumors were composed mostly of rhabdoid cells with eccentrically located nuclei, prominent nucleoli, and eosinophilic cytoplasm. We also found areas of fasciculated spindle cells, sharply separated from or irregularly admixed with areas of rhabdoid cells. There was tumor necrosis, but no epithelial areas were seen. Hemangiopericytic vasculature was at least focally observed in all cases. The tumor cells were positive for CD99 and bcl-2 in all cases and for CD56 in two cases and negative for CD34 and smooth muscle actin in all cases. The cells in case no. 1 were focally positive for cytokeratin. To verify the possibility of synovial sarcoma with rhabdoid features, reverse transcriptase polymerase chain reaction using RNA extracted from frozen tissue in case no. 1 and formalin-fixed, paraffin-embedded tissue in case nos. 2 and 3 was performed. SYT-SSX2 transcripts were detected in all 3 cases. These cases indicate that synovial sarcoma of the kidney should be considered in the differential diagnosis of mesenchymal kidney tumors with prominent rhabdoid features. A subset of adult rhabdoid tumors may be a rhabdoid variant of synovial sarcoma, and molecular studies to detect SYT-SSX fusion transcripts are recommended for an accurate diagnosis.
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PMID:Synovial sarcoma of the kidney with rhabdoid features: report of three cases. 1510 52

Extraskeletal Ewing's sarcoma (EES) is a rare soft tissue tumor morphologically indistinguishable from the more common Ewing's sarcoma of bone. We report a case of EES arising in the hard palate of 34-yr-old male patient. Microscopically, the monotonous small round cells without neuronal differentiation showed membranous positive immunoreactivity for MIC2/CD99 and vimentin. Ultrastructurally, the tumor cells showed a few intracytoplasmic organelles without evidence of neurosecretory granules or neurofilaments. The EWS-FLI1 chimeric gene was identified using the nested reverse transcriptase-polymerase chain reaction.
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PMID:Extraskeletal Ewing's sarcoma of the hard palate. 1610 Apr 68

A 7-year-old girl was hospitalized because of a tumorous mass in her left periorbital region. The tumor was removed by local excision. The soft-part tumor recurred in the parotid gland region 4 months later, and a second recurrence was noted on the left side of the neck 3 years and 3 months thereafter. The patient had not received chemotherapy or local irradiation. Histological and immunohistochemical examinations of the recurrent masses revealed morphological characteristics of small cell proliferation with desmoplastic stroma that were similar to those of the initial tumor. The cellular components showed immunoreactivity for desmin, cytokeratin, vimentin, and epithelial membrane antigen in part, but the cells were negative for myogenin, CD99, and neuron-specific enolase. These findings suggested a diagnosis of desmoplastic small cell tumor, despite its extra-abdominal location. The histological diagnosis was confirmed by reverse transcriptase polymerase chain reaction, which demonstrated an EWS-WT1 chimeric fusion gene. An in-frame fusion of EWS exon 9 and WT1 exon 8 was subsequently identified by cloning and sequencing. The chimeric fusion gene might be related to the tissue-specific phenotype of desmoplastic small cell tumors, although further investigation of this speculation is necessary.
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PMID:Desmoplastic small cell tumor of soft tissue: molecular variant of EWS-WT1 chimeric fusion. 1693 Mar 35

Ewing sarcoma/peripheral primitive neuroectodermal tumor (pPNET) is a rare primary tumor of the kidney with morphologic features similar to those of other primitive tumors. Previous studies have shown that these tumors frequently stain positively with immunostains against CD99 and FLI-1 and negatively with stains against WT-1, suggesting that these markers may be used for the distinction between Wilms tumor and pPNET. We present 30 cases of primary malignant neuroepithelial tumor with immunohistochemical profiles and reverse transcriptase polymerase chain reaction (RT-PCR) analysis and show that immunophenotypic overlap exists between Wilms tumor and pPNET. A subset of 30 neuroepithelial tumors from the National Wilms Tumor Study originally categorized as putative pPNETs of the kidney was stained with FLI-1, WT-1, and thyroid transcription factor-1. Bicolor fluorescence in situ hybridization studies were performed on 19 of the cases. Other data on these tumors were available from a previous study (Am J Surg Pathol 2001;25:133). Of 7 primary tumors that had the EWS/FLI-1 fusion transcript by RT-PCR, 6 exhibited strong immunopositivity for FLI-1. Nine that were negative by RT-PCR stained positively with the FLI-1 stain. Five fusion-negative cases stained with both FLI-1 and WT-1. Three fusion-negative cases were negative for FLI-1 but positive for WT-1. Five fusion-negative cases were negative for both FLI-1 and WT-1. Of the 30 cases, 29 were positive for CD99. Seven cases that were negative for the EWS-FLI-1 fusion by RT-PCR were positive by fluorescence in situ hybridization. All cases were negative for thyroid transcription factor-1. Reliance upon immunohistochemistry as the sole means of ancillary diagnosis in renal pPNET can lead to confusing results. We recommend molecular fusion studies for clarification of primitive renal tumors with unexpected immunophenotypic results.
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PMID:Immunohistochemistry of primary malignant neuroepithelial tumors of the kidney: a potential source of confusion? A study of 30 cases from the National Wilms Tumor Study Pathology Center. 1713 38

We report 20 cases of a distinct, previously unrecognized renal neoplasm, anaplastic sarcoma of the kidney with polyphenotypic features. The tumors were identified by re-reviewing tumors with unusual anaplastic features from the National Wilms Tumor Study Pathology Center, the International Society of Pediatric Oncology and the United Kingdom Children's Cancer Study Group trials. Patients ranged in age from 10 months to 41 years (median age 5 y, mean age 12 y) and females predominated (1.5:1). Twelve tumors presented in the right kidney, and 5 in the left (laterality was unknown in 3 cases). The most common presentation was a renal mass. Grossly, most tumors were large, measured 4 to 21 cm (mean 12.7 cm) and weighed 115 to 1820 g (mean 835 g). Seven out of 12 tumors suitable for assessment had a distinct cystic component. The tumors involved the pelvi-calyceal system in 5 of the cases. Histologically, all tumors showed a spindle cell component which contained either multiple foci or diffuse, widespread anaplastic changes with bizarre pleomorphic cells and very atypical mitotic figures. Chondroid differentiation was seen in 16 cases, usually in the form of islands of hyaline cartilage (13 cases) or chondroid matrix (3 cases). The nodules of cartilage showed both benign and malignant features, often within the same tumor. In 2 cases small foci of osteoid were found whereas osteoclast-like giant cells were seen in 4 cases. Only 3 of the tumors exhibited a primitive blastema-like area. No neoplastic epithelial structures were identified. No nephrogenic rests were found. Limited immunohistochemical studies showed vimentin positivity in 5/5 cases, desmin was positive in 4/6 cases, MYF4 showed focal weak nuclear positivity in 1/4 cases, but MyoD1 was negative in all cases (0/5). PGP9.5 was focally, strongly positive in 4/5 cases and p53 was strongly positive in 3/6 cases. Cytokeratin, using the antibody CAM5.2, was uniformly negative within the tumor cells. Finally, CD56 was focally positive in 1/6 tumors, whereas all other markers were negative including NB84a (4/4), CD34 (5/6), CD99 (5/5), and WT1 (6/6 cases). In 4 tumors reverse transcriptase-polymerase chain reaction was performed to detect the SYT-SSX fusion transcript produced by the t(x;18), and the ETV6-NTRK3 fusion transcript using RNA extracted from archived paraffin blocks-results were negative in all 4 specimens. Tumor stage was known in 15 patients including 7 stage I, 4 stage II, 3 stage III, and 1 stage IV tumors. They were usually diagnosed as anaplastic Wilms tumors and treated accordingly. Of the 13 patients with a minimum of 2 years follow-up, 4 patients developed distant metastases and 1 had local recurrence including 1 patient with stage IV, 2 with stage III, and 2 with stage I at presentation. Three of them died and 2 were lost to follow-up. One patient with stage I tumor developed widespread metastases and died. Another stage I patient developed local recurrence after 3 months of diagnosis, but was lost to follow-up. Five stage I patients were alive and free of tumor at last follow-up. The most common sites of metastases were lung (3 cases), and liver and bones (2 cases each). These tumors showed pathologic features similar to the pleuropulmonary blastoma of childhood and undifferentiated (embryonal) sarcoma of the liver. In the differential diagnosis, anaplastic Wilms tumor, primary renal synovial sarcoma, malignant mesenchymoma, ectomesenchymoma, and mesenchymal chondrosarcomas have been considered but none of these tumors shared the same features as the 20 cases described here which represent a distinct clinicopathologic entity with morphologic features of a polyphenotypic anaplastic sarcoma of the kidney. Further molecular studies are needed to better understand its nature and more accurate classification.
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PMID:Anaplastic sarcoma of the kidney: a clinicopathologic study of 20 cases of a new entity with polyphenotypic features. 1789 46


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