診断に苦慮した膝関節内ガングリオンの1例

Intra-articular Ganglion Cyst of the Knee Joint. Case Report

　診断に苦慮した膝関節内ガングリオンの1例を経験したので報告する．患者は52歳の女性で，誘因なく右膝の伸展時痛が出現した．MRI上前十字靱帯(ACL)脛骨付着部に囊胞性病変を認めたが，関節鏡では病変は確認できなかった．鏡視後1年10カ月から再び疼痛が出現した．MRIで病変の増大を認め，関節鏡を施行した．やはり腫瘤は確認できなかったが，ACL前方の正常な軟部組織を切り込むと，ゼリー状の液体流出を認めた．本例では，画像上容易に鏡視できると思われたが，軟部組織下に存在したため，一見してガングリオンは見当たらず，診断に苦慮した．

　We report a case of intra-articular ganglion cyst of the knee.　A 52-year-old woman complained of pain in her right knee on full extension.　An intra-articular ganglion cyst at the tibial insertion of the anterior cruciate ligament (ACL) was suspected based on the MRI findings.　Arthroscopy failed to reveal any evidence of a ganglion cyst.　Twenty-two months later, the patient complained of knee pain and was unable to extend her right knee.　MRI clearly showed an intra-articular ganglion cyst.　Although we were unable to see the ganglion cyst arthroscopically, we incised the soft tissue at the tibial insertion of the ACL with scissors.　We then saw gelatinous liquid flowing from the incision and removed the tissue.　Examination of tissue showed the tissue was compatible with a ganglion.　After surgery the patient's complaints improved.　It was difficult to diagnose the ganglion cyst arthroscopically, because it was located under the soft tissue at the tibial insertion of the ACL.