左膝蓋下脂肪体内に発生したガングリオンの1例

A Ganglion Cyst Arising from the Infrapatellar Fat Pad of the Knee. A Case Report

　患者は22歳の女性で，左膝痛を訴えて受診した．腫脹，可動域制限および動揺性なく，McMurrayテストは陰性であった．MRI上膝蓋腱後面の膝蓋下脂肪体内にT1強調像で低信号，T2強調像で高信号の多房性腫瘤影を認めたため，膝蓋下脂肪体内ガングリオンを疑った．鏡視では腫瘤は関節内侵入しておらず，半月板は内外側ともに断裂なく正常であった．膝蓋腱外側から展開したところ，腫瘤は関節包外の膝蓋腱後面に存在しており，半月板とは癒着していなかった．病理検査) で滑膜細胞の壁構造を認めずガングリオンと確定診断された．膝痛は消失し，再発を認めていない．

　Ganglion cysts arising in the infrapatellar fat pad of the knee joint are rare, and only a few cases have been reported on the literature.　We report the case of a ganglion cyst in the infrapatellar fat pad of a 22-year-old female.　The patient had suffered from persistent gonalgia for 2 years.　MRI showed a multilobular cyst with low T1 and high T2 signal intensity in the infrapatellar fat pad.　Arthroscopic examination showed no tears in the menisci.　The cyst was not attached to the menisci and was not observed during the arthroscopic examination.　Complete open resection was performed, and histological examination confirmed the diagnosis of ganglion cyst.　The patient has recovered and is symptom-free with no evidence of recurrence 6 months postoperatively.