The first reported case of primary common bile duct adenocarcinoma diagnosed using whole-mount tumor sections

Adenocarcinomas of the common bile duct (CBD), which account for approximately 3% of all gastrointestinal cancers, are the third most common cause of extrahepatic bile duct obstruction. Nearly, 3000 new cases of extrahepatic biliary tract cancer (excluding gallbladder cancer) are reported in the United States each year.[1,2] This condition shows a slight male predominance considering that primary sclerosing cholangitis, a known risk factor, is more common in men. Typically, affected patients are diagnosed between their sixth and seventh decade of life.[3] Here, we present a case with early-stage adenocarcinoma of the distal CBD diagnosed using whole-mount sections of the tumor specimen. A 79-year-old woman presented with epigastric pain and poor appetite for 1 month. Laboratory data showed elevated liver (glutamate pyruvate alanine aminotransferase = 1466 IU/L) and biliary (alkaline phosphatase = 172 U/L) enzymes with hyperbilirubinemia (total bilirubin = 4.5 mg/dL). Abdominal computed tomography [Figure 1] revealed dilatation of the CBD and intrahepatic ducts. The patient was subsequently admitted for suspicion of obstructive cholangitis. After admission, endoscopic retrograde cholangiopancreatography (ERCP) identified a 1.5 cm × 1 cm mass in the distal CBD, with dilatation of the distal CBD and intrahepatic bile ducts. ERCP biopsy of the distal portion of the CBD revealed poorly differentiated adenocarcinoma. The patient then underwent the Whipple procedure, with subsequent whole-mount histopathology [Figure 2, upper panel] showing poorly differentiated adenocarcinoma of the distal CBD [Figure 2, lower panel]. The pathologic tumor–node–metastasis stage was pT2, pN0, pM0, and R0. The patient exhibited good recovery after her surgery.Figure 1: Computed tomography (CT) of the abdomen. CT of the abdomen showed dilation of the common bile ductFigure 2: (A) Whole-mount section showing the anatomical localization of the common bile duct tumor and depth of invasion. (B) Histopathology examination reveals poorly differentiated adenocarcinoma (hematoxylin and eosin stain, 200×)Adenocarcinomas of the CBD are quite uncommon and carry a poor prognosis. Upon diagnosis, the majority of patients present with unresectable tumors.[4,5] Symptomatic patients with early-stage disease are even rarer and may be treated surgically. Among patients with a distal lesion, the Whipple procedure should be performed. Studies have shown that T1, T2, and T3 neoplasms have an overall 5-year survival rate of 70%, 25%, and <10%, respectively.[4,5] The presence of regional lymph node metastasis or pancreatic invasion can lead to a dismal prognosis. Adenocarcinomas of the CBD have been associated with several risk factors, with primary sclerosing cholangitis, fibropolycystic liver disease, and fluke infestation being the most important. Whole-mount sectioning involves preparing entire tissue sections serially for pathological diagnosis. This technique has been routinely used at our institute for cross-sectioning prostate specimens.[6] A whole-mount section is prepared on a large microscope slide without further sectioning into smaller fragments, allowing for the accurate determination of the anatomical location of the tumor, assessment of invasive depth, and correlation with preoperative imaging, which enhances research analysis. Unfortunately, whole-mount sectioning is not routinely used at our pathological unit due to its cumbersome workflow, technical difficulty, and high cost. Here, we present a case with surgically curable CBD cancer determined based on whole-mount sections of the tumor at our institute. In conclusion, whole-mount sectioning can reveal the anatomical location and invasive depth of a tumor. Here, we present a case with surgically curable primary CBD adenocarcinoma diagnosed using whole-mount tumor sections. Ethics statement This study was conducted in accordance with the ethical principles outlined in the Declaration of Helsinki and its amendments. The authors certify that they have obtained all appropriate patient consent form. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed. Author contributions T.-Y. T. and J.-S. J. contributed to the conceptualization and writing of this paper. H.-W. G. and Y.-C. O. contributed to the discussion. J.-K. Y. assisted with the methodology and data collection. All authors have read and approved the final version of the manuscript. Data availability statement All data generated or analyzed during this study are included in this published article. Financial support and sponsorship Nil. Conflict of interest Prof. Yen-Chuan Ou and Dr. Hong-Wei Gao, editorial board members at Tungs’ Medical Journal, had no roles in the peer review process or decision to publish this article. The other authors declared no conflicts of interest in writing this paper.