Case Report
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. May 14, 2020; 26(18): 2268-2275
Published online May 14, 2020. doi: 10.3748/wjg.v26.i18.2268
Ectopic hepatocellular carcinoma mimicking a retroperitoneal tumor: A case report
Yuki Adachi, Hiromitsu Hayashi, Toshihiko Yusa, Toru Takematsu, Kazuki Matsumura, Takaaki Higashi, Kensuke Yamamura, Takanobu Yamao, Katsunori Imai, Yo−ichi Yamashita, Hideo Baba
Yuki Adachi, Hiromitsu Hayashi, Toshihiko Yusa, Toru Takematsu, Kazuki Matsumura, Takaaki Higashi, Kensuke Yamamura, Takanobu Yamao, Katsunori Imai, Yo−ichi Yamashita, Hideo Baba, Department of Gastroenterological Surgery, Graduate School of Life Sciences, Kumamoto University, Kumamoto 8608556, Japan
Author contributions: Adachi Y and Hayashi H made substantial contributions to conception and design of the study, acquisition of data, or analysis and interpretation of data; Yusa T, Yamao T, Higashi T, Matsumura K, Yamamura K, and Imai K drafted the article and/or made critical revisions related to important intellectual content of the manuscript; all authors approved the final version of the manuscript for submission.
Informed consent statement: The patient described in this case report provided informed consent for inclusion of her medical history and course to be published.
Conflict-of-interest statement: The authors declare that they have no conflicts of interest.
CARE Checklist (2016) statement: The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Hiromitsu Hayashi, FACS, MD, PhD, Surgeon, Department of Gastroenterological Surgery, Graduate School of Life Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 8608556, Japan. hhayasi@kumamoto-u.ac.jp
Received: February 18, 2020
Peer-review started: February 18, 2020
First decision: April 8, 2020
Revised: April 22, 2020
Accepted: May 1, 2020
Article in press: May 1, 2020
Published online: May 14, 2020
Abstract
BACKGROUND

An ectopic hepatocellular carcinoma (EHCC) arises from the ectopic liver which is defined as a hepatic organ or tissue not connected to surrounding tissues. EHCC is a rare disease and it is difficult to diagnose preoperatively. Furthermore, the clinical features are not fully elucidated.

CASE SUMMARY

A retroperitoneal tumor (6 cm) was located at the dorsal side of the pancreas head on abdominal ultrasonography in an 81-year old woman positive for hepatitis C virus antibody. Contrast enhanced-computed tomography and gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging showed viable HCC patterns with early enhancement and delayed washout. The tumor markers — serum alpha-fetoprotein and alpha-fetoprotein-L3% — were increased to 30.1 ng/mL and 83.1%, respectively. Protein induced by vitamin K absence or antagonist-II was within normal levels (17 mAU/mL). Positron emission tomography-computed tomography showed strong accumulation into the tumor (Standardized Uptake Value max: 13.8), and the tumor cytology following endoscopic ultrasound-guided fine needle aspiration showed poorly differentiated carcinoma. Tumor extirpation was performed, and operative findings showed that the retroperitoneal tumor was disconnected from the pancreas and the liver. Swollen lymph nodes near the tumor were histologically normal. On histological examination, the tumor was finally diagnosed as EHCC with Arginase-1 positive expression.

CONCLUSION

We report our experience of a rare EHCC which was difficult to diagnose, and we present a review of the literature.

Keywords: Ectopic hepatocellular carcinoma, Differential diagnosis, Retroperitoneal tumor, Case report

Core tip: Ectopic liver tissue is often found on the gallbladder wall. The current case is the first ever reported case of ectopic hepatocellular carcinoma (EHCC) on the dorsal side of the pancreatic head. It is usually difficult to confirm the diagnosis of EHCC preoperatively because of the location of the mass and the rarity of this condition. In this case, we also could not make a definitive diagnosis preoperatively, but the macroscopic findings of the tumor, the immunohistological examination, and the decrease in tumor marker levels after surgery were very useful signs for the definitive diagnosis of EHCC.