Won KH, Kang EY. Differential diagnosis and treatment of foot drop caused by an extraneural ganglion cyst above the knee: A case report. World J Clin Cases 2022; 10(21): 7539-7544 [PMID: 36158030 DOI: 10.12998/wjcc.v10.i21.7539]
Corresponding Author of This Article
Ki Hong Won, MD, Doctor, Department of Rehabilitation Medicine, Kwangju Christian Hospital, Yangnim-ro 37, Gwangju 61661, South Korea. dnjsrlghd@naver.com
Research Domain of This Article
Rehabilitation
Article-Type of This Article
Case Report
Open-Access Policy of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (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/
World J Clin Cases. Jul 26, 2022; 10(21): 7539-7544 Published online Jul 26, 2022. doi: 10.12998/wjcc.v10.i21.7539
Differential diagnosis and treatment of foot drop caused by an extraneural ganglion cyst above the knee: A case report
Ki Hong Won, Eun Young Kang
Ki Hong Won, Eun Young Kang, Department of Rehabilitation Medicine, Kwangju Christian Hospital, Gwangju 61661, South Korea
Author contributions: Won KH and Kang EY contributed to this work; and both authors have read and approved the final manuscript.
Informed consent statement: Written informed consent was obtained from the patient for publication of this case report and any accompanying images.
Conflict-of-interest statement: All authors have no conflict 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: Ki Hong Won, MD, Doctor, Department of Rehabilitation Medicine, Kwangju Christian Hospital, Yangnim-ro 37, Gwangju 61661, South Korea. dnjsrlghd@naver.com
Received: February 4, 2022 Peer-review started: February 4, 2022 First decision: March 23, 2022 Revised: April 5, 2022 Accepted: May 28, 2022 Article in press: May 28, 2022 Published online: July 26, 2022 Processing time: 157 Days and 1.3 Hours
Abstract
BACKGROUND
One of the causes of foot drop is compression of the common peroneal nerve caused by space-occupying lesions such as a synovial cyst or a ganglion cyst. Most previous reports have involved compressive common peroneal neuropathy by intraneural ganglion cysts and synovial cysts. Compression of the peroneal nerve by extraneural ganglion cysts is rare. We report a rare case of compressive common peroneal neuropathy by an extraneural ganglion cyst.
CASE SUMMARY
A 46-year-old man was hospitalized after he reported a right foot drop for 1 mo. Manual muscle testing revealed scores of 1/5 on dorsiflexion of the right ankle. Hypoesthesia and paresthesia on the right lateral leg and foot dorsum were noted. He was diagnosed with a popliteal cyst by using electrophysiologic study and popliteal ultrasound (US). To facilitate common peroneal nerve (CPN) decompression, 2 cc of sticky gelatinous material was aspirated from the cyst under US guidance. Electrical stimulation and passive and assisted active ROM exercises of the right ankle and strengthening exercises for weak muscles using elastic band were prescribed based on the change of muscle power. A posterior leaf spring ankle-foot orthosis was prescribed to assist the weak dorsiflexion of the ankle. Follow-up US revealed that the cystic lesion was growing and magnetic resonance imaging demonstrated compression of the CPN by the cystic mass. The cyst was resected to prevent impending compression of the CPN.
CONCLUSION
Precise diagnosis and immediate treatment are important in cases of compressive common peroneal neuropathy caused by an extraneural cyst.
Core Tip: Nerve compression by a ganglion cyst is less common compared to other complications. Compression of the tibial nerve by a Baker’s cyst has been frequently reported. Cases of compression of the common peroneal nerve alone by an intraneural ganglion cyst have been reported sometimes. In our case, the peroneal nerve was compressed by an extraneural ganglion cyst, making it a very rare occurrence.
