Case Report
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Aug 26, 2022; 10(24): 8709-8717
Published online Aug 26, 2022. doi: 10.12998/wjcc.v10.i24.8709
Intra-abdominal ectopic bronchogenic cyst with a mucinous neoplasm harboring a GNAS mutation: A case report
Takashi Murakami, Hiroaki Shimizu, Kazuto Yamazaki, Hiroyuki Nojima, Akihiro Usui, Chihiro Kosugi, Kiyohiko Shuto, Shuntaro Obi, Takahisa Sato, Masato Yamazaki, Keiji Koda
Takashi Murakami, Hiroaki Shimizu, Hiroyuki Nojima, Akihiro Usui, Chihiro Kosugi, Kiyohiko Shuto, Masato Yamazaki, Keiji Koda, Department of Surgery, Teikyo University Chiba Medical Center, Ichihara 299-0111, Chiba, Japan
Kazuto Yamazaki, Department of Pathology, Teikyo University Chiba Medical Center, Ichihara 299-0111, Chiba, Japan
Shuntaro Obi, Takahisa Sato, Department of Internal Medicine, Teikyo University Chiba Medical Center, Ichihara 299-0111, Chiba, Japan
Author contributions: Murakami T, Shimizu H, Nojima H, and Yamazaki M performed surgery; Murakami T and Shimizu H contributed to manuscript drafting; Yamazaki K contributed to pathological diagnosis and manuscript drafting; Usui A, Kosugi C, and Shuto K contributed to preoperative diagnosis; Sato T, Obi S, and Koda K contributed to medical follow-up; Murakami T, Shimizu H, and Koda K were responsible for the manuscript revision; all authors made final approval for the manuscript to be submitted.
Informed consent statement: The patient in the present report underwent surgical resection after his informed consent was obtained.
Conflict-of-interest statement: The authors have no conflict-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: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Hiroaki Shimizu, MD, PhD, Professor, Department of Surgery, Teikyo University Chiba Medical Center, 3426-3, Anesaki, Ichihara 299-0111, Chiba, Japan. h-shimizu@med.teikyo-u.ac.jp
Received: March 10, 2022
Peer-review started: March 10, 2022
First decision: April 10, 2022
Revised: April 23, 2022
Accepted: July 18, 2022
Article in press: July 18, 2022
Published online: August 26, 2022
Processing time: 158 Days and 18.7 Hours
Abstract
BACKGROUND

Bronchogenic cysts are congenital cysts caused by abnormal sprouting from the ventral foregut during fetal life. They usually occur in the mediastinum or lung, but there are very rare cases of ectopic bronchogenic cysts that develop in the abdominal cavity. A unique intra-abdominal ectopic bronchogenic cyst with a mucinous neoplasm that was producing carcinoembryonic antigen (CEA), harboring a GNAS mutation, is reported. The present case may contribute to clarifying the mechanism of tumorigenesis and malignant transformation of ectopic bronchogenic cysts.

CASE SUMMARY

In 2007, a man in his 50s was incidentally found to have an intra-abdominal cystic mass, 8 cm in diameter. Surgical resection was recommended, but he preferred to remain under observation. In 2020, his serum CEA level increased to 26.7 ng/mL, and abdominal computed tomography showed a 15 cm × 12 cm, multifocal, cystic mass located predominantly on the lesser curvature of the stomach. Since malignancy could not be ruled out, he finally underwent surgical resection. Histologically, the cystic wall was lined by ciliated columnar epithelium, accompanied by bronchial gland-like tissue, bronchial cartilage, and smooth muscle. Part of the cyst consisted of atypical columnar epithelium with an MIB-1 index of 5% and positive for CEA. Moreover, a GNAS mutation (p.R201C) was detected in the atypical epithelium, leading to a diagnosis of an ectopic bronchogenic cyst with a low-grade mucinous neoplasm. The patient is currently undergoing outpatient follow-up without recurrence.

CONCLUSION

An extremely rare case of an abdominal bronchogenic cyst with a low-grade mucinous neoplasm harboring a GNAS mutation was reported.

Keywords: Congenital, hereditary, and neonatal diseases and abnormalities; Ectopic bronchogenic cyst; Abdominal neoplasms; GNAS mutation; Carcinoembryonic antigen; Case report

Core Tip: A man in his 60s had an intra-abdominal, 15-cm, multifocal, cystic mass located on the lesser curvature of the stomach, and he underwent surgical resection. Histologically, the resected cystic wall was lined by ciliated columnar epithelium, accompanied by bronchial gland-like tissue, bronchial cartilage, and smooth muscle. Part of the cyst consisted of atypical columnar epithelium with an MIB-1 index of 5% that was positive for carcinoembryonic antigen. Moreover, a GNAS mutation (p.R201C) was detected in the atypical epithelium, leading to a diagnosis of an ectopic bronchogenic cyst with a low-grade mucinous neoplasm.