Departments of Pathology.
Radiology.
Am J Surg Pathol. 2021 May 1;45(5):627-637. doi: 10.1097/PAS.0000000000001666.
Choledochal cyst (CC) is believed to be a mostly Asian disorder. As a clinically defined entity, its pathologic correlates are poorly characterized. Eighty-four resected CCs from the West were reanalyzed. After applying established Japanese criteria, 9/66 with available imaging were disqualified and 10/39 with preoperative cyst typing had to be recategorized. None had been diagnosed with, or evaluated for, pancreatobiliary maljunction, but on retrospective analysis of radiologic images, 12/66 were found to have pancreatobiliary maljunction. The clinical findings were: F/M=5.7; mean age, 48; most (77%) presented with abdominal pain; mean size, 2.9 cm; choledocholithiasis 11%. Gross/histologic examination revealed 3 distinct pathology-based categories: (I) Cystic dilatation of native ducts (81%). (II) Double bile duct (13%), almost all of which were found in women (10/11); all were diagnosed by pathologic examination, and not preoperative diagnosis. (III) Gastrointestinal (GI) duplication type (6%). Microscopic findings of the entire cohort included mucosal-predominant lymphoplasmacytic inflammation (50%), follicular cholangitis (7%), mucosal hyperplasia (43%; 13% with papillae), intestinal metaplasia (10%), BilIN-like hyperplasia (17%), erosion/ulceration (13%), and severe dysplasia-mimicking atypia including "detachment atypia" and micropapillary degeneration (11%). Carcinomatous changes were seen in 14 cases (17%) (high-grade dysplasia/carcinoma in situ in 7, intraductal papillary neoplasm 1, and invasive carcinoma 6); and 13/14 of these occurred in pathologic category I, all with cyst size >1 cm. In conclusion, diagnostic imaging guidelines used in Asia are not routinely used (but should be adopted) in the West. Pathologically, cases designated as CC are classifiable in 3 groups: category 1 (dilated native duct type), more prone to carcinomatous change; category 2, double-duct phenomenon (all but 1 being female in this study); and category 3, GI-type duplication. Overall, 17% of CCs show carcinomatous change (50% of them invasive). CC specimens should be carefully examined with this classification and submitted entirely for assessment of at-risk mucosa and cancerous transformation.
胆管囊状扩张症（CC）被认为主要发生在亚洲。作为一种临床定义的疾病实体，其病理相关性尚未得到充分描述。对来自西方的 84 例切除的 CC 进行了重新分析。应用日本既定标准后，9/66 例影像学资料不全被排除，10/39 例术前囊型分类有误需要重新分类。没有被诊断为或评估为胰胆管合流异常，但通过对放射影像学图像的回顾性分析，发现 12/66 例存在胰胆管合流异常。临床发现为：F/M=5.7；平均年龄为 48 岁；大多数（77%）表现为腹痛；平均大小为 2.9cm；胆总管结石 11%。大体/组织学检查显示 3 种不同的基于病理学的分类：（I）固有胆管囊性扩张（81%）。（II）双胆管（13%），几乎均见于女性（11/10）；均通过病理检查诊断，而非术前诊断。（III）胃肠道（GI）重复类型（6%）。整个队列的显微镜检查结果包括黏膜为主的淋巴浆细胞炎症（50%）、滤泡性胆管炎（7%）、黏膜增生（43%；13%伴有乳头）、肠上皮化生（10%）、BilIN 样增生（17%）、糜烂/溃疡（13%）和严重异型增生，包括“分离型异型增生”和微乳头状变性（11%）。14 例（17%）见癌性改变（高级别异型增生/原位癌 7 例，导管内乳头状肿瘤 1 例，浸润性癌 6 例）；其中 13/14 例发生在病理学分类 I 中，所有囊腔直径均>1cm。总之，亚洲使用的诊断影像学指南在西方并未常规使用（但应采用）。从病理学角度来看，被指定为 CC 的病例可分为 3 组：第 1 组（扩张固有胆管型），更易发生癌变；第 2 组，双胆管现象（本研究中所有女性）；第 3 组，胃肠道型重复。总体而言，17%的 CC 发生癌变（其中 50%为浸润性癌）。CC 标本应仔细检查并进行分类，并应全部送检，以评估高危黏膜和癌变。
