Lee Jeffrey-K, Ghosh Pradipta, McWhorter Valerie, Payne Misty, Olson Ryan, Krinsky Mary-L, Ramamoorthy Sonia, Carethers John-M
Department of Medicine, University of California, San Diego UC 303 (MC 0063), 9500 Gilman Drive, La Jolla CA 92093-0063, United States.
World J Gastroenterol. 2008 Jul 21;14(27):4389-94. doi: 10.3748/wjg.14.4389.
Sarcomatoid carcinomas of the colorectum are rare tumors 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 ultrasonography 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 adenocarcinoma. Based on the histological appearance and immunohistochemical studies, a diagnosis of sarcomatoid carcinoma was made. Only nine cases of sarcomatoid 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 adenocarcinoma 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.
结直肠肉瘤样癌是一种罕见的肿瘤，具有恶性上皮和间质成分。临床上，它们是具有早期转移的侵袭性肿瘤。由于其发病率低，发病机制尚不清楚。我们报告一例52岁女性，表现为直肠肿块和间歇性便血。结肠镜检查期间的浅表活检显示为高级别异型增生的管状绒毛状腺瘤。内镜超声检查证实肿块具有侵袭性，更深层的活检显示存在具有混合组织学成分的肿瘤。手术切除标本显示在管状绒毛状腺瘤下方存在低分化梭形细胞以及浸润性腺癌的中间阶段。根据组织学表现和免疫组化研究，诊断为肉瘤样癌。迄今为止，仅报道了9例结直肠肉瘤样癌。因此，肉瘤样癌的术语和发病机制仍具有推测性。据我们所知，这是肉瘤样癌与浸润性腺癌合并管状绒毛状腺瘤并存的首例报告；同一肿瘤内呈现出所有阶段。这一观察结果支持发病机制的“单克隆理论”，即腺瘤-肉瘤进展，伴有或不伴有癌的中间阶段。
