%0 Case Reports
%T Targeted-gene sequencing of an undifferentiated gallbladder carcinoma: a case report.
%A Xiao Y
%A Xiang C
%A Yang D
%A Zhao B
%A Li Y
%A Yin H
%J Diagn Pathol
%V 15
%N 1
%D Jun 2020 2
%M 32487254
%F 3.196
%R 10.1186/s13000-020-00981-5
%X <B>BACKGROUND: </B>Undifferentiated carcinomas of the gallbladder are extremely rare. Most undifferentiated carcinomas are accompanied by adjacent foci of other conventional carcinomas, and a transition zone is shared between them. However, genetic alterations of undifferentiated gallbladder carcinoma and the similarities or differences between the undifferentiated carcinoma and the foci conventional carcinoma are unknown.<BR><B>METHODS: </B>Herein, we report a case of undifferentiated gallbladder carcinoma with osteoclast-like giant cells with invasion into the liver, duodenum, and stomach in a 56-year-old man. The tumor was microscopically formed from the tubular adenocarcinoma (< 5% of the entire tumor), the undifferentiated carcinoma, and a transition zone between them. Four somatic mutations (TP53, TERT, ARID2, and CDH1), three amplifications (CCND1, FGF19, and MET), and a tumor mutation burden (TMB) of 3.45 muts/Mb were detected in the undifferentiated component using targeted gene sequencing, whereas 102 somatic mutations (including TP53, TERT, ARID2, and CDH1), one amplification (CCND1), and a higher TMB of 87.07 muts/Mb were detected in the tubular component. This patient died of tumor recurrence 2 months after the surgery.<BR><B>CONCLUSIONS: </B>The undifferentiated gallbladder carcinoma had its unique molecular alterations. The similarities in the genetic alterations of the undifferentiated carcinoma and adenocarcinoma provide evidence of a common origin at the genetic level. The occurrence of an undifferentiated carcinoma may be due to heterogeneity-associated branched evolution from the tubular adenocarcinoma.