主肺動脈にまで達した巨大右房粘液腫の1例

A Case of Giant Right Atrial Myxoma which had Extended to the Pulmonary Artery

　心臓粘液腫は左心房に好発し，右心房に発生する症例は欧米では約20％程度であるが，本邦の統計では8.5％と少ない．今回，われわれは主肺動脈にまで達する巨大右房粘液腫の1例を経験したので報告する．症例は63歳，男性．1996年1月頃より労作時の息切れが出現し，改善しないため当科を受診した．経胸壁心エコーで右房内に腫瘍像を認めた．経食道心エコーにて腫瘍像は心房中隔に茎を持ち，内部エコーが不均一な八頭状で可動性があったため，粘液腫を疑った．その腫瘍像は右房より，三尖弁を越えて右室内腔をほぼ占拠し，肺動脈弁を越えて主肺動脈にまで達していた．手術所見では，腫瘍は冠状静脈洞開口部と卵円窩の中間部より生じ，三尖弁口をほぼ閉鎖し，右室から肺動脈弁方向に進展していた．腫瘍は重量が112g，容積が106cm³であり，組織学的に粘液腫であった．本例では自覚症状の出現が遅かったため，長時間を経過し，腫瘍が巨大となり主肺動脈にまで発育したものと思われた．

There are some reports concerning operations for right atrial myxoma. But an atrial myxoma extending to the pulmonary artery is rare. A 63-year-old man was admitted to our hospital because of shortness of breath or exertion. On physical examination, a diastolic mur-mur was heard in the left fourth intercostal space. His transthoracic echocardiogram revealed a large oval heterogenous mass in the right atrium. Transesophageal echocardiogram revealed the atrial mass clearly. It was attached to the atrial septum with a short stalk. This mass extended to the pulmonary artery through the right ventricule from the right atrium. Surgical excision of the mass was undertaken. A solid mass measuring 112g was attached below the fossa ovalis of the atrial septum with a short stalk. Pathological examination showed myxomatous tissue. Since the operation, the patient's shortness of breath has disappeared. Because there was no subjective symptom in this case, it is concluded that the right atrial myxoma had extended to the pulmonary artery.