Case Report
Copyright ©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Apr 16, 2023; 11(11): 2521-2527
Published online Apr 16, 2023. doi: 10.12998/wjcc.v11.i11.2521
SMARCA4-deficient undifferentiated thoracic tumor: A case report
Hee Jung Kwon, Min Hye Jang
Hee Jung Kwon, Min Hye Jang, Department of Pathology, Yeungnam University Medical Center, Daegu 42415, South Korea
Author contributions: Kwon HJ and Jang MH contributed to manuscript writing and editing and data collection; Kwon HJ contributed to data analysis; Jang MH contributed to conceptualization and supervision; all authors have read and approved the final manuscript.
Supported by a grant from Yeungnam University, No. 222A580017.
Informed consent statement: The study protocol was approved by the Institutional Review Board of the Yeungnam University Medical Center with a waiver of informed consent.
Conflict-of-interest statement: The authors declare that they have no conflict of interest to disclose.
CARE Checklist (2016) statement: The authors have read the CARE Checklist (2016), and the manuscript has been 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: Min Hye Jang, MD, PhD, Assistant Professor, Department of Pathology, Yeungnam University Medical Center, 170, Hyeonchung-ro, Nam-gu, Daegu 42415, South Korea. clodious@ynu.ac.kr
Received: December 20, 2022
Peer-review started: December 20, 2022
First decision: February 17, 2023
Revised: February 27, 2023
Accepted: March 22, 2023
Article in press: March 22, 2023
Published online: April 16, 2023
Abstract
BACKGROUND

SMARCA4-deficient undifferentiated tumors (SMARCA4-DUTs) present with diverse clinical manifestations and progress to metastasis and even cause death within a few months. This novel subset of undifferentiated tumors occurs in the middle-aged population and is strongly associated with a smoking history. Distinguishing it from other malignancies is challenging.

CASE SUMMARY

A 62-year-old man presented with chest pain for 7 d. The patient had no respiratory symptoms and normal pulmonary function test results. The patient had been a smoker for 8 years and quit smoking 2 years ago. Chest computed tomography revealed a huge mass involving the left upper and lower lung lobes with pericardial invasion and multiple metastases. Tumor samples were obtained using open frozen biopsy, after several unsuccessful attempts. The tumor was composed of sheets of undifferentiated disclosive cells with vesicular nuclei and prominent nucleoli. The differential diagnosis included high-grade lymphoma, germ cell tumor, NUT carcinoma, undifferentiated carcinoma, and sarcoma. The tumor cells were large, arranged in sheets, and did not exhibit glandular or squamous differentiation. Frequent foci of necrosis were noted. There was no evidence of epithelial differentiation on immunohistochemical staining. The SMARCA4 stain showed complete loss of expression of SMARCA4, which is diagnostic.

CONCLUSION

In the present case, thoracic SMARCA4-DUT was diagnosed based on clinical features, absence of epithelial differentiation, and negative SMARCA4 expression.

Keywords: SMARCA4, BRG1, Deficient, Undifferentiated tumor, Thoracic, Case report

Core Tip: SMARCA4-deficient undifferentiated tumors are highly aggressive neoplasms. Here, we report a case of a SMARCA4-deficient undifferentiated tumor with characteristic clinical and histological features. The findings of this case could serve as a resource for future studies.