僧帽弁輪石灰化を起源とする左室流出路腫瘤に対し摘出術を施行した慢性透析患者の1例

Surgical Removal of Severe Mitral Annular Calcification in the Left Ventricular Outflow Tract Mimicking an Intracardiac Tumor in a Hemo-dialysis Patient:A case report

　症例は69歳，男性．1987年洞不全症候群に対しAAIペースメーカー植え込み施行，1995年2月generator交換目的に入院，現在無症状．既往歴は1991年糖尿病性腎症による慢性腎不全で人工透析導入，現在週3回の慢性透析中．入院時の断層心エコーで僧帽弁輪の高度石灰化，左室流出路に直径約1cmでエコー輝度の高い可動性腫瘤を認めた．経食道心エコーでも同様の所見．冠動脈造影では栄養血管は認めず，可動性のため塞栓の危険性が高いと考え1995年3月29日摘出術を施行した．手術は体外循環下に経大動脈弁的に摘出．右・無冠尖交連の下方，僧帽弁前尖弁輪付近に白色一部赤色の硬い8×3mm大の腫瘤を認め，鉗子で容易に摘出できた．病理所見は高度な石灰沈着を伴うverruca様組織で，表面は結合織で被われていた．僧帽弁の弁輪石灰化が左房や左室流入路側に成長するという報告はあるが，本例のように左室流出路側に腫瘤として突出するのは非常に稀である．

This report describes a rare case of a left ventricular tumor originating from severe mitral annular calcification in a chronic hemo-dialysis patient.

The 69-year-old male had under gone pacemaker implantation for sick sinus syndrome in 1987. After being admitted for replacement of the pacemaker gen-erator. coincidental transthoracic and transesophageal echocardiography revealed a tumor of the left ventricular outflow tract with a size of 8 mm×3mm. The tumor was close to the aortic valve and the ante-rior leaflet of the mitral valve. The echodensity was suggestive of mitral annular calcification. Although the lesions seemed to produce no ill-effects, surgical removal of the tumor was carried out in March, 1995, taking into consideration the risk of embolization. Histological examination revealed the tumor to be calcification. We suggest that the tumor was caused by severe mitral annular calcification.