Case Report
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Jan 16, 2021; 9(2): 429-435
Published online Jan 16, 2021. doi: 10.12998/wjcc.v9.i2.429
Inflammatory myofibroblastic tumor successfully treated with metformin: A case report and review of literature
Yu Liang, Hong-Xiang Gao, Rui-Cheng Tian, Jing Wang, Yu-Hua Shan, Lei Zhang, Chen-Jie Xie, Jing-Jing Li, Min Xu, Song Gu
Yu Liang, Hong-Xiang Gao, Rui-Cheng Tian, Jing Wang, Yu-Hua Shan, Lei Zhang, Chen-Jie Xie, Jing-Jing Li, Min Xu, Song Gu, Department of Surgery, Shanghai Children’s Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, China
Author contributions: Liang Y, Gao HX, Tian RC, and Wang J reviewed the literature and contributed to manuscript drafting; Shan YH and Zhang L analyzed and interpreted the imaging findings; Xie CJ and Li JJ were responsible for the revision of the manuscript for important intellectual content; all authors issued final approval for the version to be submitted; Gu S and Xu M performed the disease consultation and drafted the manuscript.
Supported by Shanghai Science and Technology Committee, No. 17441903200 and No. 17411950400.
Informed consent statement: Informed written consent was obtained from the patient’s parents for publication of this report and any accompanying images.
Conflict-of-interest statement: The authors declare that they have no conflict of interest to report.
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:
Corresponding author: Song Gu, PhD, Associate Professor, Department of Surgery, Shanghai Children’s Medical Center, Shanghai Jiaotong University School of Medicine, No. 1678 Dongfang Road, Pudong District, Shanghai 200127, China.
Received: August 14, 2020
Peer-review started: August 14, 2020
First decision: November 14, 2020
Revised: November 20, 2020
Accepted: November 29, 2020
Article in press: November 29, 2020
Published online: January 16, 2021

Inflammatory myofibroblastic tumor (IMT) is a distinct tumor with a low incidence rate, which can be diagnosed at any age with a predilection for children and adolescents. Although IMT is visible in any tissues and organs, it is more commonly found in the lungs. The clinical and radiological manifestations of IMT lack specificity, hence resulting in frequent misdiagnosis. Surgical resection is currently the main therapeutic approach for IMT. Only scarce cases of IMT treated with metformin have been reported. Here we report the case of an IMT patient with partial penile resection treated with metformin.


A 1-year-old boy was born with a shorter penis, and his foreskin could not be completely turned over. When he was 6 month old, a well-circumscribed mass on the glans was found, while it did not attract the attention of his parents. The mass gradually increased in size over time before he was admitted to the hospital, where physical examination was performed. It was revealed that the glans hidden behind the foreskin had a mass with a diameter of about 4 cm surrounding the penis. The mass appeared to be hard with a smooth surface and poor mobility. The two testicles examined at the bottom of the scrotum were revealed to have a normal size. Magnetic resonance imaging showed a tumor with rich blood supply encircling the cavernosum with a size of 3.5 cm × 2.1 cm × 2.0 cm. A thick urinary line was found without urine dripping, urgency, and urodynia. Surgical treatment was performed. During the operation, it was observed that the mass had surrounded and invaded the cavernosum without obvious boundaries, and that the tumor occupied about one-half of the penis cross-section as well as infiltrated more than one-half of the glans. In addition, the tumor had caused urethral invasion and anterior urethrostenosis. With the intention of keeping the glans and cavernosum, the tumor at the anterior urethra was partially removed, leaving about 30% of the tumor mass. Pathology analysis demonstrated that the tumor was rich in spindle cells with infiltration of inflammatory cells. Immuno-histochemistry analysis indicated that the cells were positive for CD4, CD99, Ki67, BCL2, and CD68, and negative for ALK, MyoG, S100, SOX10, PR, and EMA. Hence, the tumor was diagnosed as IMT. Metformin was prescribed for the patient after the operation, following which an oral dose of 7 mg/kg was given three times a day after meals. Three months later, it was observed that the remaining tumor had completely disappeared and that the urination process from the urethra opening had resumed normal. In addition, there were no side effects observed. There was also no tumor recurrence. The growth and development of the boy were unaffected as a result of the treatment.


The tumor was observed to have completely disappeared after treatment with metformin. Our finding is of great significance to facilitate future clinical treatment with IMT.

Keywords: Inflammatory myofibroblastic tumor, Metformin, Therapeutic, Case report, Adenosine phosphate protein kinase, mTOR

Core Tip: Inflammatory myofibroblastic tumor (IMT) is a rare tumor in children, with surgical resection being the main treatment approach. We report a case of penile IMT with complete surgical resection. The residual lesions were found to have completely disappeared after treatment with metformin, a traditional drug.