膝関節内と交通を持つ巨大ガングリオンの1例

Huge Ganglion Connected to the Knee Joint Space. Case Report

　症例は77歳の女性で，右膝関節内側に9×8cmという巨大な腫瘤像を呈した半月ガングリオンの稀な1例を経験した．MRIでは腫瘤は内側半月に隣接していた．関節鏡視下半月部分切除と観血的腫瘤切除を行ったところ，腫瘤と関節内の交通部を認めた．また，交通部にはチェックバルブ様機構の存在を示唆する所見を認め，巨大化の一因となったことが考えられた．関節鏡視下半月部分切除と観血的腫瘤切除を行い，再発なく良好な経過であった．

　We report a rare case of a meniscal ganglion in a 77-year-old female who presented with a huge mass (9 cm × 8 cm) on the medial aspect of the right knee.　The mass was observed to be located adjacent to the medial meniscus on MRI (magnetic resonance imaging).　Arthroscopic partial meniscectomy and open resection of the ganglion were perfomed, and we observed a communication between the ganglion and the knee joint space.　The communication revealed the presence of a mechanism that functioned like a check valve, thereby enlarging the ganglion until it became a huge mass.　The surgical outcome was good, and there is no evidence of recurrence as of five months after arthroscopic partial meniscectomy and open resection of the ganglion.