Division of Gastroenterology and Hepatology, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
Dig Dis Sci. 2024 Aug;69(8):2734-2740. doi: 10.1007/s10620-024-08524-4. Epub 2024 Aug 1.
The z-line refers to the squamocolumnar junction which marks the transition between the normal stratified squamous epithelium of the distal esophagus and the columnar epithelium of the gastric cardia. An "irregular" z-line refers to an irregular appearing squamocolumnar junction characterized by the presence of columnar mucosa less than 1 cm in length that extends above the gastroesophageal junction. In contrast, Barrett's esophagus is diagnosed when columnar mucosa of at least 1 cm is seen in the distal esophagus extending above the gastroesophageal junction with biopsies demonstrating specialized intestinal metaplasia. Current guidelines recommend against taking routine biopsies from a normal or irregular z-line in the absence of visible abnormalities and advise against endoscopic surveillance in this patient population, in large part due to multiple studies demonstrating lack of progression to advanced neoplasia such as high-grade dysplasia or esophageal adenocarcinoma in patients with an irregular z-line. Despite these recommendations, a sizable number of patients without Barrett's esophagus undergo biopsies from the z-line and are subsequently recommended to have surveillance endoscopies. Furthermore, patients with an irregular z-line are often mislabelled as Barrett's esophagus resulting in significant downstream consequences including higher healthcare costs and reduced health-related quality of life. In this review, we highlight the importance of landmark identification of the distal esophagus and gastroesophageal junction at the time of endoscopy, share recommendations from current guidelines related to the z-line, examine rates of neoplastic progression in those with an irregular z-line, discuss consequences of routinely biopsying an irregular z-line, and highlight strategies on how to approach an irregular z-line if seen on endoscopy. A careful, high-quality endoscopic examination can help to identify visible abnormalities at the z-line, which, if present, should be targeted for biopsies to rule out dysplasia and neoplasia.
Z 线是指鳞柱状交界线，标志着远端食管正常复层鳞状上皮与胃贲门部柱状上皮的过渡。“不规则”Z 线是指外观不规则的鳞柱状交界线，其特征是存在长度小于 1 厘米的柱状黏膜，延伸超过胃食管交界线。相比之下，当在胃食管交界线以上的远端食管中看到至少 1 厘米长的柱状黏膜，并通过活检显示出特殊的肠上皮化生时，才诊断为 Barrett 食管。目前的指南建议在没有可见异常的情况下，不要对正常或不规则的 Z 线进行常规活检，也不建议对该患者人群进行内镜监测，这主要是因为多项研究表明，在存在不规则 Z 线的患者中，进展为高级别瘤变（如高级别异型增生或食管腺癌）的可能性较低。尽管有这些建议，但仍有相当数量的非 Barrett 食管患者接受 Z 线活检，并随后被建议进行监测性内镜检查。此外，存在不规则 Z 线的患者经常被误诊为 Barrett 食管，导致严重的下游后果，包括更高的医疗保健成本和降低的健康相关生活质量。在这篇综述中，我们强调了在进行内镜检查时识别远端食管和胃食管交界线的重要性，分享了与 Z 线相关的现行指南建议，检查了存在不规则 Z 线的患者中肿瘤进展的发生率，讨论了常规活检不规则 Z 线的后果，并强调了如果在内镜检查中发现不规则 Z 线时应如何处理的策略。仔细、高质量的内镜检查可以帮助识别 Z 线处的可见异常，如果存在，则应针对活检以排除异型增生和肿瘤。
