Case Report
Copyright ©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Jan 6, 2023; 11(1): 233-241
Published online Jan 6, 2023. doi: 10.12998/wjcc.v11.i1.233
Malignant transformation of pulmonary bronchiolar adenoma into mucinous adenocarcinoma: A case report
Xu-Ling Liu, Cheng-Feng Miao, Min Li, Peng Li
Xu-Ling Liu, Cheng-Feng Miao, Min Li, Peng Li, Department of Pathology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, Zhejiang Province, China
Author contributions: Liu XL is the first author and prepared the manuscript under the supervision of Li P; each author made substantial contributions to the conception and design of this paper; all authors read and approved the final version of the manuscript.
Supported by the Science and Technology Plan Project of Wenzhou, China, No. Y20190117; and the Natural Science Foundation of Zhejiang Province, China, No. LQ21H090017.
Informed consent statement: Informed written informed consent was obtained from the patient for publication of this report and any accompanying images.
Conflict-of-interest statement: All the authors declare that they have no conflicts of interest to disclose.
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: Peng Li, MM, Associate Chief Physician, Department of Pathology, The First Affiliated Hospital of Wenzhou Medical University, Xuefu Road, Ouhai District, Wenzhou 325000, Zhejiang Province, China. lipenglimo@163.com
Received: October 24, 2022
Peer-review started: October 24, 2022
First decision: November 11, 2022
Revised: November 24, 2022
Accepted: December 15, 2022
Article in press: December 15, 2022
Published online: January 6, 2023
Abstract
BACKGROUND

Bronchiolar adenoma (BA) and ciliated muconodular papillary tumor are rare tumors that have bilayered cell proliferation and continuous expression of p40 and CK5/6 in the basal cell layer. Diagnosis is difficult because of the limited knowledge of these tumors and their morphological similarities to malignant tumors, including invasive mucinous adenocarcinoma, especially based on the histopathology of intraoperative frozen sections. These tumors are now considered to be benign neoplasms, with malignant transformation reported in only a few cases.

CASE SUMMARY

A 57-year-old woman presented with a 17.0 mm × 7.0 mm nodule in the lower lobe of the left lung. Hematoxylin-eosin staining and immunohistochemistry of a surgical specimen were performed. The tumor consisted of a BA area and a mucinous adenocarcinoma (MA) area. In the BA area, the tumor had a bilayered structure of luminal cells and basal cells. The basal cells were positive for CK5/6 and p40, but the MA area was negative for these biomarkers. The Ki-67 proliferation index was low (1%-2%). The patient was diagnosed with BA accompanied by MA, and had a favorable outcome.

CONCLUSION

The present study indicated that BA may be carcinogenic, and suggests that clinicians should be aware of its potential for malignant transformation.

Keywords: Bronchiolar adenoma, Ciliated muconodular papillary tumors, Mucinous adenocarcinoma, Malignant transformation, Pulmonary, Case report

Core Tip: This study adds to the currently limited information regarding the malignant transformation of pulmonary bronchiolar adenomas into mucinous adenocarcinomas. Our results suggest clinicians should have a high index of suspicion when encountering a lesion that appears to be benign.