僧帽弁に生じたgiant Lambl's excrescenceの1切除例

A Case Report of Resected Giant Lambl's Excrescence of the Mitral Valve

要旨　患者は56歳，男性．拡張型心筋症，心房細動のため当院内科で経過観察されていたところ，経食道心臓超音波検査にて僧帽弁前尖に数mm大の結節エコー像が認められたため，当科に紹介された．経胸壁心臓超音波検査では軽度の僧帽弁逆流を認めるのみで同様のエコー像は認められなかった．胸部CT検査では心臓内に腫瘍像は認め得なかった．以上より僧帽弁に生じた心臓腫瘍，特にその超音波所見，部位より，乳頭状線維弾性腫を疑い手術を施行した．常温体外循環，blood cardioplegiaによる心停止下に僧帽弁前尖弁膜中央にある腫瘍状物質を切除した．肉眼的には直径7mm，有茎乳頭状であり，組織学的には内皮細胞に囲まれた細胞質の少ない硝子化した線維体で，giant Lambl's excrescenceと診断された．Lambl's excrescenceは心臓腫瘍状物質の中でも比較的稀であり，自験例のごとく拡張型心筋症との合併例の報告はこれまで認められない．

　We report a case of giant Lambl's excrescence in a 56-year-old man. During medical follow-up for dilatedcardiomyopathy (DCM) and atrial fibrillation (Af), transesophageal echocardiography revealed a massattached to the anterior leaflet of the mitral valve. Transthoracic echocardiography revealed mitral regurgitation but failed to detect the mass. Neither couldcomputed tomography (CT) detect the cardiac mass.

　Under the diagnosis of papillary fibroelastoma of themitral valve, an operation was performed. The masswas completely resected under blood cardioplegic heartarrest, while using normothermic cardiopulmonary bypass and preserving the mitral valve. The specimen wasa papillary tumor, 7mm in diameter. The pathohistological finding was a hypocellular hyalinized fibrousmass surrounded by endothelium cells, which indicatedgiant Lambl's excrescence of the mitral valve.

　Lambl's excrescence is a relatively rare pathology. No case with DCM like this one has been reportedbefore.