Evaluation and Pathologic Classification of Choledochal Cysts Clinicopathologic Analysis of 84 Cases From the West

Aydin Mericoz C., Hacihasanoglu E., Muraki T., Pehlivanoglu B., Memis B., Mittal P., ...More

AMERICAN JOURNAL OF SURGICAL PATHOLOGY, vol.45, no.5, pp.627-637, 2021 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 45 Issue: 5
  • Publication Date: 2021
  • Doi Number: 10.1097/pas.0000000000001666
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, BIOSIS, EMBASE, MEDLINE
  • Page Numbers: pp.627-637
  • Keywords: choledochal cysts, pancreatobiliary maljunction (PBM), carcinomatous changes, dysplasia, COMMON BILE-DUCT, DIFFERENTIAL-DIAGNOSIS, PANCREATITIS, AUTOIMMUNE, MALIGNANCY, BRUSHINGS, FEATURES, PROPOSAL, LESIONS, REFLUX
  • Dokuz Eylül University Affiliated: No


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.