Levy Angela D, Sobin Leslie H
Department of Radiologic Pathology, Armed Forces Institute of Pathology, Alaska and Fern Sts NW, Washington, DC 20306-6000, USA.
Radiographics. 2007 Jan-Feb;27(1):237-57. doi: 10.1148/rg.271065169.
Gastrointestinal carcinoids are well-differentiated endocrine neoplasms that belong to a diverse group of tumors that arise from cells of the diffuse endocrine system. A wide variety of specialized endocrine cells that populate the gastrointestinal mucosa and submucosa give rise to carcinoids. Consequently, carcinoids may occur throughout the gastrointestinal tract and produce a variety of hormones and protein products that are associated with specific clinical symptoms. Biologic behavior of carcinoids varies by site and cell type, but all gastrointestinal carcinoids are considered to have malignant potential. They may produce specific syndromes such as Zollinger-Ellison syndrome, or they may occur in association with inherited syndromes such as multiple endocrine neoplasia type 1 or neurofibromatosis type 1. Metastatic carcinoids may produce carcinoid syndrome. The small intestine is the most common location for gastrointestinal carcinoids. Most small intestinal carcinoids arise from enterochromaffin cells of the distal ileum that produce serotonin. Small intestinal carcinoids often have an aggressive biologic behavior and, as such, patients frequently have metastases to regional lymph nodes and the liver at initial presentation. Pathologic and radiologic manifestations of serotonin-producing small intestinal carcinoids are related to local and regional effects of serotonin and its metabolites. In contrast, carcinoids of the appendix and rectum are commonly discovered incidentally as small lesions that are unassociated with clinical evidence of hormone production and have a more indolent clinical course. Carcinoids of the stomach, duodenum, and colon are uncommon but have distinctive clinical, pathologic, and radiologic appearances. Knowledge of the diverse clinical, pathologic, and radiologic spectrum of gastrointestinal carcinoids is important in the imaging and management of patients with suspected carcinoids or focal gastrointestinal masses.
胃肠道类癌是分化良好的内分泌肿瘤，属于源自弥漫性内分泌系统细胞的多种肿瘤。分布于胃肠道黏膜和黏膜下层的多种特殊内分泌细胞可引发类癌。因此，类癌可发生于整个胃肠道，并产生多种与特定临床症状相关的激素和蛋白质产物。类癌的生物学行为因部位和细胞类型而异，但所有胃肠道类癌都被认为具有恶性潜能。它们可能产生特定综合征，如卓 - 艾综合征，或可能与遗传性综合征相关，如1型多发性内分泌腺瘤或1型神经纤维瘤病。转移性类癌可能产生类癌综合征。小肠是胃肠道类癌最常见的发生部位。大多数小肠类癌起源于产生5-羟色胺的回肠末端肠嗜铬细胞。小肠类癌通常具有侵袭性生物学行为，因此患者在初次就诊时常常已有区域淋巴结和肝脏转移。产生5-羟色胺的小肠类癌的病理和影像学表现与5-羟色胺及其代谢产物的局部和区域效应有关。相比之下，阑尾和直肠类癌通常是偶然发现的小病变，与激素产生的临床证据无关，临床病程较为惰性。胃、十二指肠和结肠类癌不常见，但具有独特的临床、病理和影像学表现。了解胃肠道类癌多样的临床、病理和影像学特征对于疑似类癌或局灶性胃肠道肿块患者的影像学检查和管理很重要。
