Akiyama Shintaro, Kikuchi Daisuke, Mitani Toshifumi, Fujii Takeshi, Yamada Akihiro, Matsui Akira, Ogawa Osamu, Iizuka Toshiro, Hoteya Shu, Kaise Mitsuru
From the Department of Gastroenterology (SA, DK, TM, AY, AM, OO, TI, SH, MK); and Department of Pathology (TF), Toranomon Hospital, Tokyo, Japan.
Medicine (Baltimore). 2015 Jan;94(4):e493. doi: 10.1097/MD.0000000000000493.
Mucinous adenocarcinoma (MC) is a unique pathological type of colorectal cancer (CRC). The development of MC is often associated with intestinal inflammation and/or microsatellite instability (MSI). Moreover, MC has clinicopathological characteristics that render making the correct diagnosis difficult such as extramural progression. Meanwhile, intestinal spirochetosis (IS) is a condition in which colonic epithelial cells are colonized and/or infected by spirochetes. Intestinal inflammation due to IS occurs by the destruction of colonic microvilli and induces chronic diarrhea. Recently, it was reported that the prevalence of IS tended to be high in patients with sessile serrated adenomas/polyps, the precursor of MSI-high CRC including MC. This study presents a case of MC in the setting of intestinal inflammation due to IS and tries to clarify the cause of MC development by performing immunohistochemical stain of resected specimen for DNA mismatch repair (MMR) proteins. This patient is a 63-year-old man with no symptoms who had a positive fecal occult blood test. Subsequent endoscopic findings and biopsy results revealed intestinal stricture of the transverse colon and chronic infective colitis associated with IS. Metronidazole therapy was initiated but was not effective. Although follow-up colonoscopy was performed repeatedly, intestinal perforation occurred 20 months later. Subtotal colectomy and ileostomy were performed. Pathological examination of resected specimens revealed MC with normal expression of MMR proteins, including MLH1, MSH2, MSH6, and PMS2. The histopathological classification was Union for International Cancer Control (UICC) IIIB and adjuvant chemotherapy was initiated. This is an interesting case of MC developing in the setting of chronic colitis associated with IS. It seemed that the cause of MC development was not MSI but intestinal inflammation. Besides, endoscopic diagnosis of MC in this case was difficult because of the extramural progression and lack of obvious atypical colonic glands in biopsy specimens. This report provides evidence for an association between neoplasm and IS-induced intestinal inflammation. Moreover, we suggest that making the diagnosis of MC could be difficult because of its unique clinicopathological characteristics.
黏液腺癌（MC）是结直肠癌（CRC）的一种独特病理类型。MC的发生常与肠道炎症和/或微卫星不稳定性（MSI）相关。此外，MC具有使正确诊断变得困难的临床病理特征，如壁外进展。同时，肠道螺旋体病（IS）是一种结肠上皮细胞被螺旋体定植和/或感染的疾病。由IS引起的肠道炎症通过结肠微绒毛的破坏而发生，并诱发慢性腹泻。最近有报道称，在无蒂锯齿状腺瘤/息肉患者中，IS的患病率往往较高，无蒂锯齿状腺瘤/息肉是包括MC在内的MSI-H CRC的前体。本研究报告了一例因IS导致肠道炎症背景下的MC病例，并试图通过对切除标本进行DNA错配修复（MMR）蛋白的免疫组化染色来阐明MC发生的原因。该患者为一名63岁男性，无症状，粪便潜血试验呈阳性。随后的内镜检查结果和活检结果显示横结肠肠道狭窄以及与IS相关的慢性感染性结肠炎。开始使用甲硝唑治疗但无效。尽管反复进行了结肠镜随访，但20个月后发生了肠穿孔。实施了次全结肠切除术和回肠造口术。切除标本的病理检查显示为MC，MMR蛋白包括MLH1、MSH2、MSH6和PMS2表达正常。组织病理学分类为国际癌症控制联盟（UICC）IIIB期，并开始辅助化疗。这是一例在与IS相关的慢性结肠炎背景下发生MC的有趣病例。似乎MC发生的原因不是MSI而是肠道炎症。此外，由于壁外进展以及活检标本中缺乏明显的非典型结肠腺管，该病例中MC的内镜诊断困难。本报告为肿瘤与IS诱导的肠道炎症之间的关联提供了证据。此外，我们认为由于MC独特的临床病理特征，其诊断可能会很困难。
