Three cases of desmoplastic small round cell tumor (DSRCT) with multiphenotypic differentiation, primary in the pleura, are presented. This is a previously unrecognized site for this tumor type. Two ...patients were male and one female aged 29, 24, and 17 years. All presented with chest pain and were found to have pleural-based tumors associated with pleural effusion. Abdominal involvement was not present in any of the cases. Histologically, the tumor showed the characteristic features of intra-abdominal DSRCT, including angulated nests of small cells embedded in a vascular fibroblastic stroma, focal rhabdoid phenotype, and areas of central necrosis. The neoplastic cells showed evidence of epithelial, mesenchymal, and neural differentiation with characteristic dot-like positivity for vimentin and desmin topographically corresponding to perinuclear aggregates of intermediate filaments identified on electron microscopy in one case. Two patients died of disease 2 years and 15 months after presentation, respectively, and one patient is alive with disease 18 months after presentation. The histogenesis of DSRCT is unknown. Most previously reported cases involved the peritoneum or tunica vaginalis, suggesting a histogenetic relationship to the mesothelium. The occurrence of these tumors in the pleura lends further support to this theory.
Solar cells have generated a lot of interest as a potential source of clean renewable energy for the future. However, a big bottleneck in wide scale deployment of these energy sources remain in the ...low efficiency of these conversion devices. Recently, the use of nanostructures and the strategy of quantum confinement has become a general approach towards better charge carrier generation and capture. In this article, we have presented calculations on the optical characteristics of nanowires made out of silicon. Our calculations show these nanowires form excellent optoelectronic materials and may yield efficient photovoltaic devices.
Dysgerminoma has traditionally been considered an end-stage neoplasm without potential for further differentiation. Although there have been several reports of transformation of testicular seminoma ...to yolk sac tumor, a similar event has not been previously reported in dysgerminoma of the ovary. Three cases of ovarian germ cell tumor (two pure dysgerminomas and one mixed germ cell tumor with dysgerminoma and yolk sac components) that revealed histologic changes compatible with early transformation to yolk sac tumor are described. In general, the areas of transformation were located at the periphery of the tumor lobules which otherwise had features of typical dysgerminoma. They were characterized by the presence of microcysts and small glandular structures, which though not readily identified on H&E became more evident with stains for keratins, alpha-fetoprotein, and blood group-related antigen. The small size and focal nature of change, and the apparent transition favor the interpretation that this change represents transformation rather than admixture of two germ cell components. The relationship of dysgerminoma to the solid variant of yolk sac tumor is discussed and an alternate histogenetic scheme in which dysgerminoma represents the stage of earliest differentiation from which other non dysgerminomatous tumors may arise is presented. Although previously proposed for testicular germ cell neoplasia, this scheme has not yet been applied to their ovarian counterparts.
Most tumors arising in the nasopharynx are either squamous cell carcinoma or so-called undifferentiated carcinoma of the nasopharyngeal type. Primary adenocarcinomas of the nasopharynx are rare, and ...glandular differentiation in undifferentiated carcinoma of the nasopharyngeal type has not been reported to date. We report 2 cases of undifferentiated carcinoma of the nasopharyngeal type that show distinct glandular differentiation by light microscopy, histochemistry, immunohistochemistry, and ultrastructure. Both tumors showed equal positivity for Epstein-Barr virus latent membrane protein and in situ hybridization for Epstein-Barr virus genome in the undifferentiated areas of the tumor and those featuring glandular differentiation.
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