Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0035412 (rhabdomyosarcoma)
 6,156 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

PURPOSE. Rhabdomyosarcoma is the most common primary orbital malignant tumor in children. Though rare above the age of twenty, the authors present a case of primary orbital rhabdomyosarcoma in an adult and review the literature. DESIGN. Clinico-pathologic case report. METHODS. A 34-year-old man presented with a recurrent orbital tumor four years after initial excision. This tumor was initially misdiagnosed elsewhere as Merkel cell tumor on the basis of spurious immunohistochemical studies. Excision biopsy of the recurrent orbital mass was performed. MAIN OUTCOME MEASURES. MRI of the orbit and brain was done as well as histopathologic examination and immunohistochemistry of the excised mass. RESULTS. Histopathologic study of the excised orbital tumor revealed rhabdomyosarcoma. CONCLUSION. Careful microscopic evaluation and immunohistochemical stains are important in confirming the diagnosis of atypical cases of orbital tumors.
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PMID:Primary orbital rhabdomyosarcoma in an adult. 1204 83

The current study disusses a new approach to the group of small round cell tumors (SRCTs) independently of their primary anatomical location. We perform this analysis supported mainly by morphological means and particularly with the help of immunohistochemistry and electron microscopy; the last of which continues to play a decisive role in their differential diagnosis. The microscopical similarity of many of these tumors often makes the diagnosis in routine histology extremely difficult, due to the varying degree of heterogeneity present, and may have important therapeutic and prognostic implications. Thus a correct final diagnosis is mandatory for the clinic. Within the group of tumors that express a dominant or occasional small round cell pattern "SRCT" (neoplasms of the Central Nervous System excluded) are included: Ewing's sarcoma and peripheral neuroectodermal tumor (Es/pPNET) comprising its varieties, neuroblastoma, desmoplastic small round cell tumor, rhabdomyosarcoma, alveolar, solid and embryonal, small cell osteosarcoma, chondrosarcoma, myxoid and mesenchymal, round cell and myxoid liposarcoma, synovial sarcoma (monophasic undiffentiated), primitive malignant peripheral nerve sheath tumor (malignant small cell schwannoma), malignant non-Hogdkin lymphoma, Merkel cell tumor of the skin (small cell carcinoma including neuroendocrine carcinoma). This study discusses in each case not only the histology, supported by immunohistochemistry, but also the main ultrastructural characteristics. We are conscious that in some cases further cytogenetic or molecular biology support may be necessary, when considering the limits of morphology today. Thus, short references on molecular genetics, complementing the structural findings, are given.
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PMID:Electron microscopy and other ancillary techniques in the diagnosis of small round cell tumors. 1269 73

PAX5 is a member of the paired box transcription factors involved in development and its expression has been well characterized among hematopoietic malignancies of B-cell lineage. Its expression has also been reported in a subset of neuroendocrine carcinomas, urothelial tumors, Merkel cell carcinoma, glioblastoma, and neuroblastoma cell lines. As such, we sought to assess it as a diagnostic marker in the evaluation of pediatric small round blue cell tumors. Tumors selected for evaluation included embryonal rhabdomyosarcoma (55 cases), alveolar rhabdomyosarcoma (ARMS) (51 cases), neuroblastoma (22 cases), Wilms tumor (18 cases), Ewing Family of Tumors (11 cases), lymphoblastic lymphoma (8 cases), hepatoblastoma (6 cases), and granulocytic sarcoma (3 cases) as either cores in a tissue microarray or whole mount sections. All cases were immunostained using an antibody directed toward PAX5 and immunoreactivity was scored semiquantitatively according to percentage of nuclear staining. As expected, all B-cell lymphoblastic lymphomas were strongly immunoreactive against PAX5. Additionally, all Wilms tumors showed staining of variable intensity, most intensely in the epithelial component. Of the rhabdomyosarcoma cases, 34 of 51 (67%) ARMS were immunoreactive whereas none of the 55 embryonal rhabdomyosarcoma cases stained. No other tumor type on the array was immunoreactive toward PAX5. Genetic information was available on 7 ARMS, 5 of which had characteristic translocations involving PAX genes, either t(2:13) or t(1;13). Of the translocation-positive cases, all showed nuclear reactivity toward PAX5, and both the translocation-negative cases did not. Possible explanations of PAX5 staining include aberrant expression of the PAX5 transcription factor, PAX5 expression in normal tissue at the time the tumors most closely recapitulates in development or crossreactivity with another member of the PAX family. PAX3 and PAX7 fusion genes characterize the majority of ARMS making crossreactivity with these proteins an attractive theory, and suggest that PAX5 immunoreactivity may be specific for translocation-positive ARMS. Further study in a larger series of rhabdomyosarcomas is warranted to assess the sensitivity and specificity of PAX5 immunoreactivity for the ARMS variant.
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PMID:PAX immunoreactivity identifies alveolar rhabdomyosarcoma. 1914 2

Merkel cell carcinoma (MCC) represents an uncommon and lethal form of cutaneous malignancy. Historically, the pathogenesis of MCC has been presumed to be linked to ultraviolet light overexposure, but recently, it has been documented that some examples harbor polyomavirus genome, the presence of which is presumed to be of pathogenetic importance. Extremely rare cases of MCC may show heterologous differentiation. We report an example of MCC with heterologous rhabdomyosarcomatous differentiation, the third such case to date, with emphasis on its distinction from fusion-negative alveolar rhabdomyosarcoma. The role of immunohistochemistry for Merkel cell polyomavirus large T-antigen in this differential diagnosis is emphasized.
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PMID:Merkel cell carcinoma with heterologous rhabdomyoblastic differentiation: the role of immunohistochemistry for Merkel cell polyomavirus large T-antigen in confirmation. 2203 37