Case Report
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Oct 26, 2021; 9(30): 9285-9294
Published online Oct 26, 2021. doi: 10.12998/wjcc.v9.i30.9285
Skeletal muscle metastasis with bone metaplasia from colon cancer: A case report and review of the literature
Yu Guo, Shuang Wang, Ze-Yun Zhao, Jian-Nan Li, An Shang, Dong-Lin Li, Min Wang
Yu Guo, Ze-Yun Zhao, Jian-Nan Li, An Shang, Dong-Lin Li, Min Wang, Department of General Surgery, The Second Hospital of Jilin University, Changchun 130000, Jilin Province, China
Shuang Wang, Department of Dermatology, The Second Hospital of Jilin University, Changchun 130000, Jilin Province, China
Author contributions: Guo Y, Wang S, and Wang M contributed to the conceptualization; Guo Y, Zhao ZY, Shang A, and Li DL contributed to the data curation; Li JN and Wang M contributed to the supervision; Guo Y contributed to the drafting, review, and editing of the manuscript.
Supported by the Science and Technology Development Project of Jilin Province, No. 3D5197434429; the Youth Program of the National Natural Science Foundation of China, No. 3A4205367429; and the Education Project of Jilin University; No. 419070600046.
Informed consent statement: Written informed consent was obtained from the patient for the publication of this case report and the accompanying images..
Conflict-of-interest statement: The authors declare that they have no competing interests to report.
CARE Checklist (2016) statement: The writing of this article complies with the CARE Checklist (2016) statement.
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: Min Wang, PhD, Full Professor, Department of General Surgery, The Second Hospital of Jilin University, Changchun, Jilin Province, No. 218 Ziqiang Street, Nanguan District, Changchun 130000, Jilin Province, China. jdeywangmin@163.com
Received: June 3, 2021
Peer-review started: June 3, 2021
First decision: June 25, 2021
Revised: June 30, 2021
Accepted: August 23, 2021
Article in press: August 23, 2021
Published online: October 26, 2021
Processing time: 140 Days and 1.5 Hours
Abstract
BACKGROUND

Colon cancer is a common malignant disease of the gastrointestinal tract and usually occurs at the junction of the rectum and sigmoid colon. Lymphatic and hematogenous metastases occur frequently in colon cancer and the most common metastatic sites include the liver, lung, peritoneum, bone, and lymph nodes. As a manifestation of advanced tumor spread and metastasis, soft tissue metastasis, especially skeletal muscle metastasis with bone metaplasia caused by colon cancer, is rare, accounting for less than 1% of metastases.

CASE SUMMARY

A 43-year-old male patient developed skeletal muscle metastasis with bone metaplasia of the right proximal thigh 5 mo after colon cancer was diagnosed. The patient was admitted to the hospital because of pain caused by a local mass on his right thigh. Positron emission tomography-computed tomography showed many enlarged lymph nodes around the abdominal aorta but no signs of lung or liver metastases. Color ultrasound revealed a mass located in the skeletal muscle and the results of histological biopsy revealed a poorly differentiated adenocarcinoma suspected to be distant metastases from colon cancer. Immunohistochemistry showed small woven bone components that were considered to be ossified.

CONCLUSION

This case reminds us that for patients with advanced colorectal tumors, we should be alert to the possibility of unconventional metastasis.

Keywords: Soft tissue metastasis; Skeletal muscle metastasis; Ossification; Colon cancer; BRAF mutation; Tumor mutation burden; Case report

Core Tip: In this article, we report a rare case of a 43-year-old male patient who developed skeletal muscle metastasis with bone metaplasia of the right proximal thigh 5 mo after colon cancer was diagnosed. This article discusses the possible mechanism of epithelial to mesenchymal transition from the perspective of BRAF mutation and tumor mutation burden. It prompts the need to guard against the occurrence of secondary malignant tumors with unusual metastasis pathways in patients with advanced colorectal cancer (CRC). It also reminds us to pay attention to unexplained masses and other discomforts in patients with advanced CRC.