Clinicopathological Characteristics of Extrahepatic Biliary Neuroendocrine Neoplasms in the Gallbladder, Extrahepatic Biliary Tract, and Ampulla of Vater: A Single-Center Cross-Sectional Study

BackgroundSignificant changes were made in the grading and staging systems for neuroendocrine neoplasms (NENs) in 2017. Therefore, a clinical report to comprehensively update the clinicopathological characteristics, therapeutic approaches, and prognosis of these patients should be drafted.MethodsWe retrospectively reviewed a database of 16 patients who developed NENs or mixed endocrine non-endocrine neoplasms (MiNENs) after curative resection. Among them, eight had ampulla of Vater (AoV) tumors, and eight had non-AoV tumors. One patient had NEN Grade 1, five had NEN Grade 2, and five had NEN Grade 3 (G3); all had poorly differentiated neuroendocrine carcinoma. Five patients had MiNEN or combined carcinoma.ResultsThe mean age was 57.88 years. The overall survival rates after curative surgery at 1, 3, and 5 years were 87.1, 80.4, and 71.4%, respectively. The 1-, 3-, and 5-year disease-free survival rates were 87.1%, 79.8%, and 71.8%, respectively. In univariate analysis, age >65 years, mitotic count (>20/10 high-power fields), Ki-67 index >20%, and presence of stones were significant prognosticators, whereas only the mitotic count was statistically significant in the multivariate analysis. Age >65 years (p=0.039), a Ki-67 index >20% (p=0.03), presence of stones (p=0.021), G3 stage disease, MiNEN (p=0.002), or perineural invasion (p<0.001) were more frequently observed in the non-AoV group than in the AoV group.ConclusionHigh mitosis count had a greater effect on extrahepatic biliary NEN than the tumor-node-metastasis staging system. Patients with AoV tumors had better prognostic predictor factors compared to those with non-AoV tumors.