Sarcomatoid carcinomas of the colorectum are rare tu- mors that display both malignant epithelial and stromal components. Clinically, they are aggressive tumors with early metastasis. Due to their infrequent occurrenc...Sarcomatoid carcinomas of the colorectum are rare tu- mors that display both malignant epithelial and stromal components. Clinically, they are aggressive tumors with early metastasis. Due to their infrequent occurrence, the pathogenesis is poorly understood. We report a case of a 52-year-old woman who presented with a rectal mass and intermittent hematochezia. Superficial biopsies during colonoscopy revealed a tubulovillous adenoma with high-grade dysplasia. Endoscopic ultra- sonography confirmed an invasive nature of the mass, and deeper biopsies revealed the presence of neoplasm with mixed histological components. The surgically- excised specimen demonstrated the presence of poorly differentiated spindle cells underneath the tubulovillous adenoma and an intermediate stage of invasive adeno- carcinoma. Based on the histological appearance and immunohistochemical studies, a diagnosis of sarcoma- toid carcinoma was made. Only nine cases of sarcoma- toid carcinomas of the colorectum have been reported to date. As a result, the terminology and pathogenesis of sarcomatoid carcinoma remain speculative. To the best of our knowledge, this is the first report of co- existence of sarcomatoid carcinoma and invasive ad- enocarcinoma with tubulovillous adenoma; all stages represented within the same tumor. This observation supports the "monoclonal theory" of pathogenesis with an adenoma-sarcoma progression with or without an intermediate stage of carcinoma.展开更多
Since the derivation of embryonic stem （ES） cell lines from human blastocysts in 1998 [1], ES cells have emerged as a potential source of cells and tissues that could be used for cell replacement therapy of incurabl...Since the derivation of embryonic stem （ES） cell lines from human blastocysts in 1998 [1], ES cells have emerged as a potential source of cells and tissues that could be used for cell replacement therapy of incurable degenerative diseases. This is due to their remarkable pluripotency, which enables them to differentiate into any adult cell type of the three embryonal germ layers. Indeed, several groups have reported the successful differentiation of ES cells into adult-type cell lineages including, but not limited to： cardiomyocytes, hematopoietic cells, hepatocytes,展开更多
文摘Sarcomatoid carcinomas of the colorectum are rare tu- mors that display both malignant epithelial and stromal components. Clinically, they are aggressive tumors with early metastasis. Due to their infrequent occurrence, the pathogenesis is poorly understood. We report a case of a 52-year-old woman who presented with a rectal mass and intermittent hematochezia. Superficial biopsies during colonoscopy revealed a tubulovillous adenoma with high-grade dysplasia. Endoscopic ultra- sonography confirmed an invasive nature of the mass, and deeper biopsies revealed the presence of neoplasm with mixed histological components. The surgically- excised specimen demonstrated the presence of poorly differentiated spindle cells underneath the tubulovillous adenoma and an intermediate stage of invasive adeno- carcinoma. Based on the histological appearance and immunohistochemical studies, a diagnosis of sarcoma- toid carcinoma was made. Only nine cases of sarcoma- toid carcinomas of the colorectum have been reported to date. As a result, the terminology and pathogenesis of sarcomatoid carcinoma remain speculative. To the best of our knowledge, this is the first report of co- existence of sarcomatoid carcinoma and invasive ad- enocarcinoma with tubulovillous adenoma; all stages represented within the same tumor. This observation supports the "monoclonal theory" of pathogenesis with an adenoma-sarcoma progression with or without an intermediate stage of carcinoma.
文摘Since the derivation of embryonic stem （ES） cell lines from human blastocysts in 1998 [1], ES cells have emerged as a potential source of cells and tissues that could be used for cell replacement therapy of incurable degenerative diseases. This is due to their remarkable pluripotency, which enables them to differentiate into any adult cell type of the three embryonal germ layers. Indeed, several groups have reported the successful differentiation of ES cells into adult-type cell lineages including, but not limited to： cardiomyocytes, hematopoietic cells, hepatocytes,
