Case ReportMixed adenoneuroendocrine carcinoma derived from the cystic duct: A case report

- We report here an extremely rare case of mixed adenoneuroendocrine carcinomas (MANECs) derived from cystic duct. Histologically, the tumor had components of both well-differentiated tubular adenocarcinoma and neuroendocrine carcinoma with massive venous invasion.
- R0 resection was established, but the risk of recurrence in liver was estimated to be significantly high, due to the detected venous invasion of the neuroendocrine carcinoma in the resection margin of the hepatic duct. Eight months after surgery, multiple liver metastases were discovered, and treatment with adjuvant chemotherapy was initiated.
- Though standards of diagnosis and treatment for MANECs of the bile duct have not been established, multidisciplinary therapy is necessary to improve outcomes.

IntroductionMixed adenoneuroendocrine carcinomas (MANECs) derived from cystic duct are extremely rare.Presentation of caseAn 80-year-old woman was admitted to the department of surgery, Onomichi general hospital with abnormal liver function and jaundice. Enhanced abdominal computed tomography (CT) detected a well-enhanced papillary tumor in the cystic duct, which protruded into the common bile duct. The intrahepatic bile duct was dilated due to tumor obstruction. The entire tumor showed high intensity in T2-weighted magnetic resonance imaging (MRI) imaging. Endoscopic retrograde cholangiopancreatography (ERCP) showed that the tumor ranged from part of communication of three ducts (cystic, common hepatic and common bile duct), to the middle of common bile duct. Biliary cytology determined a class V malignancy (adenocarcinoma). Endoscopic ultrasound determined that the tumor was primarily at the cystic duct with heterogeneous echoic pattern, which extended into the common bile duct. The preoperative diagnosis was cystic duct carcinoma (T3N0M0, StageIIIA). An extended cholecystectomy with regional lymph nodes dissection was performed. Histologically, the tumor had components of both well-differentiated tubular adenocarcinoma and neuroendocrine carcinoma, which is classified as MANECs according to the 2010 WHO classification of endocrine tumors. Eight months after surgery, multiple liver metastases were discovered, and treatment with adjuvant chemotherapy was initiated.DisscusionWe present a rare case of MANECs derived from cystic duct. Until now, an established adjuvant systemic chemotherapy has not emerged, and curative resection, with poor long-term prognosis, remains the only treatment option.ConclusionThough standards of treatment for MANECs have not been established,multidisciplinary theraphy is necessary to improve outcome.