PDF(Pubmed)
Abstract：
Composite intestinal adenoma-microcarcinoid (CIAM) is a rare intestinal lesion consisting of conventional adenoma and small, well differentiated carcinoid [microcarcinoid (MC)] at its base. The incidence of CIAM is 3.8% in surgically resected colorectal polyps. While its pathogenesis is unknown, studies support the role of Wnt/β-catenin pathway in the tumorigenesis of CIAM. CIAMs have been primarily reported in the colon wherein they present as polyps with well-defined margins, similar to conventional adenomatous polyps. MC is usually found in adenomatous polyps with high-risk features such as large size, villous architecture, or high grade dysplasia. Histologically, the MC component is often multifocal and spans 3.9 to 5.8 millimeters in size. MC is usually confined within the mucosa but occasional CIAM cases with MC extending to the submucosa have been reported. MC of CIAM demonstrates bland cytology and inconspicuous proliferative activity. The lesional cells are positive for synaptophysin and 60% to 100% of cases show nuclear β-catenin positivity. MC poses a diagnostic challenge with its morphologic and immunohistochemical resemblance to both benign and malignant lesions, including squamous morules/metaplasia, adenocarcinoma, squamous cell carcinoma, sporadic neuroendocrine tumor and goblet cell adenocarcinoma. CIAM is an indolent lesion with a favorable outcome. Complete removal by polypectomy is considered curative. Awareness and recognition of this rare entity will help arrive at correct diagnosis and improve patient care. Currently, CIAM is not recognized as a subtype of mixed neuroendocrine-non-neuroendocrine neoplasm by WHO.
摘要：
复合肠腺瘤-微类癌（CIAM）是一种罕见的肠道病变，由常规腺瘤和小，在其基础上分化良好的类癌[微类癌（MC）]。手术切除的结直肠息肉中CIAM的发生率为3.8%。虽然其发病机制尚不清楚,研究支持Wnt/β-catenin通路在CIAM肿瘤发生中的作用。CIAMs主要在结肠中报道，它们表现为边缘明确的息肉，与常规腺瘤性息肉相似。MC通常存在于腺瘤性息肉中，具有大尺寸等高风险特征，绒毛建筑，或高度发育不良。组织学上,MC组件通常是多焦点的，尺寸跨度为3.9至5.8毫米。MC通常局限在粘膜内，但已报道了MC延伸至粘膜下层的CIAM病例。CIAM的MC表现出温和的细胞学和不明显的增殖活性。病变细胞对突触素呈阳性，60％至100％的病例显示核β-连环蛋白阳性。MC以其与良性和恶性病变的形态学和免疫组织化学相似性提出了诊断挑战。包括鳞状小孢子/化生，腺癌,鳞状细胞癌,散发性神经内分泌肿瘤和杯状细胞腺癌。CIAM是一种惰性病变，预后良好。通过息肉切除术完全切除被认为是治愈性的。对这种罕见实体的认识和认识将有助于得出正确的诊断并改善患者护理。目前,WHO未将CIAM视为混合性神经内分泌-非神经内分泌肿瘤的亚型。
