Weekly Case

Title : Case 563

Age / Sex : 60 / M


Chief complaint :


Numbness in lateral aspect of left lower leg and foot dorsum + footdrop



What is your impression?

Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer).

Courtesy of Hyun Su Kim, Samsung medical center



Discussion


Answer:  


Intraneural ganglia


 


Findings:


Multilobulated cystic lesion adjacent to the proximal tibiofibular joint extending along the course of deep peroneal nerve articular branch and common peroneal nerve is seen.


Increased signal intensity of left tibialis anterior muscle represents denervation edema in the anterior compartment muscle.


 


Differential Diagnosis:


Extraneural ganglia


Cystic nerve sheath tumors


 


Discussion:


Intraneural ganglia are non-neoplastic cysts that are contained within the epineurium of peripheral nerves. Many nerves are affected by these cysts, but the common peroneal nerve at the fibular neck is by far the most frequent site. Numerous explanations have been proposed for the pathogenesis. According to the unifying articular theory, fluid from the synovial joints dissects intraepineurally from the joint via articular branches perforating the joint capsule along a path of least resistance.


 For intraneural ganglia of peroneal nerve, three signs on axial MRI have been described as follows;


 



  • Transverse limb sign: cyst within the articular branch as it cross over the anterior surface of the fibular neck; and the “ signet ring ” sign,


 



  • Signet ring sign: eccentric cyst within the outer epineurium of the common peroneal nerve


 



  • Tail sign: a cystic connection between the articular branch of the common peroneal nerve and the joint.


 


For treatment of intraneural ganglia, decompression of the cyst through a limited epineurotomy along with disconnection of the articular branch (to eliminate intraneural recurrences) can be performed.


 


 


References:


Robert J. Spinner et al. Skeletal Radiol (2008) 37:1091 – 1099


Robert J. Spinner et al. J Neurosurg 2003; 99: 330 – 343



Correct Answer
Total applicants 35 Correct answers 25
Name Institution
전성희 전문의
최수연 전문의
이영선 전문의
김동환 서울아산병원, 전문의
김태형 전문의
장성원 중앙보훈병원, 전공의
서지운 전문의
김미선 전문의
장민영 국민건강보험공단 일산병원, 전문의
이혜란 전문의
박선영 한림대학교 성심병원, 전문의
윤유성 구례병원, 전문의
김보람 전문의
박준동 뿌리병원, 전문의
권기언 명지병원, 전공의
김지은 서울대학교병원, 전공의
전인환 전문의
서지원 전문의
윤재성 서울아산병원, 전문의
박서영 전문의
김창현 전문의
여유진 전문의
노근탁 전문의
이지현 병무청, 전문의
최희석 전병원, 전문의
Semi-Correct Answer
Total applicants 35 Semi-Correct answers 8
김민선 인하대병원, 전문의
이은채 전문의
이규정 고대구로병원, 전공의
김유진 전문의
라요한 성균관대학교 삼성서울병원, 전문의
박재일 대구 척탑병원, 전문의
정소용 생생병원, 전문의
김동찬 전문의


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