Histological Features Responsible for Brownish Epithelium in Squamous Neoplasia of the Esophagus by Narrow Band Imaging

Hiromitsu Kanzaki; Ryu Ishihara; Shingo Ishiguro; Kengo Nagai; Fumi Matsui; Takeshi Yamashina; Takashi Ohta; Sachiko Yamamoto; Noboru Hanaoka; Masao Hanafusa; Yoji Takeuchi; Koji Higashino; Noriya Uedo; Hiroyasu Iishi; Yasuhiko Tomita


J Gastroenterol Hepatol. 2013;28(2):274-278. 

In This Article

Abstract and Introduction


Background and Aim: Esophageal squamous neoplasias usually appear brown under narrow band imaging as a result of microvascular proliferation, and brownish color changes in the areas between vessels, referred to as brownish epithelium. However, the reasons for the development of this brownish epithelium and its clinical implications have not been fully investigated.

Methods: Patients with superficial esophageal neoplasias treated by endoscopic resection were included in the study. Areas of mucosa with brownish and non-brownish epithelia were evaluated histologically.

Results: A total of 68 superficial esophageal neoplasias in 58 patients were included in the analysis. Of the 68 lesions, 32 were classified in the brownish epithelium group, and 36 in the non-brownish epithelium group. Brownish epithelium was significantly associated with a diagnosis of high-grade intraepithelial neoplasia or invasive cancer (P < 0.0001). Thinning of the keratinous layer, thinning of the epithelium, and cellular atypia were significantly associated with brownish epithelium by univariate analysis, and thinning of the keratinous layer and thinning of the epithelium were confirmed to be independent factors by multivariate analysis. The odds ratios were 9.6 (95% confidence interval: 2.0–46.3) for thinning of the keratinous layer, and 4.6 (95% confidence interval: 1.1–19.4) for thinning of the epithelium.

Conclusions: Brownish epithelium is an important finding in the diagnosis of esophageal squamous neoplasia, and may be related to thinning of the keratinous layer, caused by neoplastic cell proliferation, and thinning of the epithelium.


Esophageal cancer is the sixth most common cause of cancer-related mortality worldwide.[1] The overall survival of patients with esophageal cancer, regardless of its histological type, remains poor. However, a favorable prognosis can be expected if this cancer is detected at an early stage.[2–5] Endoscopic examination has been reported to be useful for the early detection of esophageal cancer,[6–14] but the usefulness of conventional endoscopy is currently limited because of its poor ability to detect early neoplastic changes.[6,7] Narrow band imaging (NBI) is a non-invasive optical technique that uses reflected light to visualize the organ surface.[8] NBI can enhance the superficial structure and facilitate the detection of neoplastic lesions,[9–11] and is regarded as the standard modality for screening of esophageal squamous neoplasias.[9–14]

Lesions that are suspicious for esophageal squamous neoplasias usually appear brown when using NBI. Brownish areas are regarded as a red-flag sign for esophageal neoplasia, and their importance in the screening of esophageal neoplasias has been confirmed in previous studies.[9,10,12,13,15,16] Brownish areas comprise areas of microvascular proliferation, with brownish color changes in the areas between vessels, referred to as brownish epithelium.[17] The vascular architecture changes during cancer development, and previous studies have performed detailed analyses of the vascular changes seen in esophageal cancer.[9,17,18] However, the cause of the brownish epithelium and its clinical implications have not been fully investigated. A better knowledge of the reasons for the development of brownish epithelium may improve our understanding of the lesion's character, and increase the chances of its accurate diagnosis. This study, therefore, aimed to clarify the histological changes responsible for the development of the brownish epithelium in esophageal squamous neoplasia.