Department of Clinical Oncology, The Chinese University of Hong Kong, Hong Kong SAR, China.
J Dig Dis. 2010 Aug;11(4):201-7. doi: 10.1111/j.1751-2980.2010.00439.x.
The existence of flat adenomas in the colon is well recognized. Whether they represent a distinct disease with a pathogenetic pathway different from that of the classical adenoma-carcinoma sequence in colorectal tumorigenesis and have higher malignant potential remains a matter of debate. To review the epidemiology, clinical features, detection and management of flat and depressed (non-polypoid) colonic neoplasm, we performed a thorough literature review on studies focusing on the prevalence, histological features, genetics, detection and treatment of flat and depressed (non-polypoid) colonic neoplasm. A high percentage of severe dysplasia in flat colonic adenomas has not been consistently demonstrated. Their malignant potential appears to be size-dependent. Flat adenomas are found to have a lower incidence of major genetic abnormalities involved in the classical adenoma-carcinoma sequence and that has raised suspicions that they may have a different pathogenesis. The depressed type of colorectal carcinoma is uncommon but shows more aggressive behavior. More advanced colonoscopic techniques, such as chromoendoscopy, may enhance the detection of small and inconspicuous colonic neoplastic lesions that lack a protruding configuration. It is essential for endoscopists to appreciate the existence and clinical significance of flat and depressed colonic lesions as an important variant of colonic neoplasms so that the goal of reducing colorectal carcinoma incidence by polypectomy can be better achieved.
结肠平坦型腺瘤的存在已得到广泛认可。然而，它们是否代表一种独特的疾病，其发病机制与结直肠肿瘤发生中的经典腺瘤-癌序列不同，且具有更高的恶性潜能，仍存在争议。为了回顾平坦型和凹陷型（非息肉样）结肠肿瘤的流行病学、临床特征、检测和管理，我们对聚焦于平坦型和凹陷型（非息肉样）结肠肿瘤的患病率、组织学特征、遗传学、检测和治疗的研究进行了全面的文献回顾。虽然有研究表明，大部分平坦型结直肠腺瘤存在重度异型增生，但这种情况并不常见。其恶性潜能似乎与肿瘤大小有关。与经典腺瘤-癌序列相关的主要遗传异常在平坦型腺瘤中发生率较低，这引发了人们对其可能具有不同发病机制的怀疑。凹陷型结直肠癌并不常见，但表现出更具侵袭性的行为。更先进的结肠镜技术，如染色内镜，可能会提高对缺乏突出形态的小而不明显的结肠肿瘤性病变的检测能力。内镜医生必须认识到平坦型和凹陷型结肠病变的存在及其临床意义，因为它们是结直肠肿瘤的一种重要变异，这对于通过息肉切除术降低结直肠癌发病率的目标至关重要。
