Redefining resection margins and dissection planes in perihilar cholangiocarcinoma-radical resection is a rare event.

Radical tumor resection (pR0) is prognostic for disease-free and overall survival after resection of perihilar cholangiocarcinoma (pCCA). However, no universal agreement exists on the definition of radical resection and histopathological reporting. The aim of this study was to provide a standardized protocol for histopathological assessment and reporting of the surgical specimen obtained after resection for pCCA. All consecutive patients operated for pCCA with curative intent at the Karolinska University Hospital, Stockholm, Sweden between 2012 and 2021 were included. A standardized protocol for histopathological assessment and reporting of the surgical specimen after liver resection for pCCA is presented. A detailed mapping of the transection margins and dissection planes was performed. The results of applying different existing pR0 definitions were compared. Sixty-eight patients with pCCA were included. Five transection margins and two dissection planes were defined. By defining pR0 as cancer-free margins and planes tolerating distances <1mm, the pR0 rate was 66%. However, when pR0 was set as >1mm from invasive cancer to all resection margins and dissection planes, the pR0 rate fell to 16%. This study supports the use of thorough and standardized pathological handling, assessment and reporting of resection margins and dissection planes of surgical specimens of pCCA.

Correction: Immunohistochemical Typing of Adenocarcinomas of the Pancreatobiliary System Improves Diagnosis and Prognostic Stratification.

[This corrects the article DOI: 10.1371/journal.pone.0166067.].

Immunohistochemical Typing of Adenocarcinomas of the Pancreatobiliary System Improves Diagnosis and Prognostic Stratification.

BACKGROUND & AIMS: Adenocarcinomas of the pancreatobiliary system are currently classified by their primary anatomical location. In particular, the pathological diagnosis of intrahepatic cholangiocarcinoma is still considered as a diagnosis of exclusion of metastatic adenocarcinoma. Periampullary cancers have been previously classified according to the histological type of differentiation (pancreatobiliary, intestinal), but overlapping morphological features hinder their differential diagnosis. We performed an integrative immunohistochemical analysis of pancreato-biliary tumors to improve their diagnosis and prediction of outcome. METHODS: This was a retrospective observational cohort study on patients with adenocarcinoma of the pancreatobiliary system who underwent diagnostic core needle biopsy or surgical resection at a tertiary referral center. 409 tumor samples were analyzed with up to 27 conventional antibodies used in diagnostic pathology. Immunohistochemical scoring system was the percentage of stained tumor cells. Bioinformatic analysis, internal validation, and survival analysis were performed. RESULTS: Hierarchical clustering and differential expression analysis identified three immunohistochemical tumor types (extrahepatic pancreatobiliary, intestinal, and intrahepatic cholangiocarcinoma) and the discriminant markers between them. Among patients who underwent surgical resection of their primary tumor with curative intent, the intestinal type showed an adjusted hazard ratio of 0.19 for overall survival (95% confidence interval 0.05-0.72; p value = 0.014) compared to the extrahepatic pancreatobiliary type. CONCLUSIONS: Integrative immunohistochemical classification of adenocarcinomas of the pancreatobiliary system results in a characteristic immunohistochemical profile for intrahepatic cholangiocarcinoma and intestinal type adenocarcinoma, which helps in distinguishing them from metastatic and pancreatobiliary type adenocarcinoma, respectively. A diagnostic immunohistochemical panel and additional extended panels of discriminant markers are proposed as guidance for their pathological diagnosis.