Case Report
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Feb 16, 2021; 9(5): 1111-1118
Published online Feb 16, 2021. doi: 10.12998/wjcc.v9.i5.1111
Imaging characteristics of a rare case of monostotic fibrous dysplasia of the sacrum: A case report
Xin-Xin Liu, Xin Xin, Yu-Hong Yan, Xiao-Wen Ma
Xin-Xin Liu, Yu-Hong Yan, Xiao-Wen Ma, MRI Department, Honghui Hospital, Xi'an Jiaotong University, Xi'an 710054, Shaanxi Province, China
Xin Xin, Department of Orthopaedics, Ankang Center Hospital, Ankang 725000, Shaanxi Province, China
Author contributions: Xin X and Yan YH contributed to the literature search; Liu XX contributed to design of the research and writing of the manuscript; Ma XW supervised the study and revised the manuscript. All authors have read and approved the final manuscript.
Informed consent statement: Informed written consent was obtained from the patient for publication of this report and any accompanying images.
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: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Xiao-Wen Ma, MSc, Professor, MRI Department, Honghui Hospital, Xi'an Jiaotong University, No. 555 Youyi East Road, Beilin District, Xi'an 710054, Shaanxi Province, China. yxmxw@126.com
Received: August 29, 2020
First decision: November 3, 2020
Revised: November 14, 2020
Accepted: December 6, 2020
Article in press: December 6, 2020
Published online: February 16, 2021
Processing time: 154 Days and 8.4 Hours
Abstract
BACKGROUND

Fibrous dysplasia (FD) is a common benign intramedullary fibro-osseous lesion. Involvement of the spine is rare, with the literature including only case reports, and cases of monostotic FD (MFD) in the sacrum are extremely rare. A correct preoperative diagnosis of spinal MFD is important for clinicians to select proper treatment.

CASE SUMMARY

We retrospectively assessed a case report of MFD in the sacrum. This patient was examined by computed tomography (CT) and magnetic resonance imaging (MRI), and the diagnosis was confirmed by pathology. A review of the literature was performed to analyze the imaging characteristics and differential diagnoses of spinal MFD. For our patient, the CT scan showed the lesion to be expansile, with ground glass opacity and a sclerotic rim. On MRI, the lesion showed iso-low signal intensity on T1WI and iso-high signal intensity on T2WI. A low signal rim was found on T1WI and T2WI. Our patient was treated by posterior focal excision, decompression, bone grafting, fusion and pedicle screw fixation. A satisfactory result was achieved, with pain disappearance. No complications had occurred at the 1-year follow up.

CONCLUSION

MFD is an expansile osteolytic change. Ground glass opacity and a sclerotic margin are obvious characteristics. The lesion often involves the vertebral body and posterior element. Knowledge of these imaging characteristics of spinal FD could be helpful for diagnosis and prevent unnecessary procedures.

Keywords: Monostotic; Sacrum; Fibrous dysplasia; Spine; Computed tomographic; Case report; Magnetic resonance imaging

Core Tip: This report presents a rare case of monostotic fibrous dysplasia (MFD) involving the sacrum. The imaging manifestations of MFD include expansile lesions, ground glass opacity, and sclerotic rims. Most lesions show iso-low signal intensity on T1WI and iso-high signal intensity on T2WI. These features can provide a suggestive diagnosis to distinguish MFD from giant cell tumour, aneurysmal bone cyst, and vertebral haemangioma. Accurate diagnosis of MFD in the spine is of great value for clinicians to choose an appropriate treatment.