山崎 正之¹, 竹内 陽史郎², 石上 晃子³, 吉永 仁香¹, 堀家 由貴¹, 小川 正子¹, 藤田 淳子¹, 高岡 理恵¹, 望月 泰秀⁴, 志手 淳也⁴

Masayuki YAMASAKI¹, Yoshio TAKEUCHI², Akiko ISHIGAMI³, Kimika YOSHINAGA¹, Yuki HORIKE¹, Shoko OGAWA¹, Junko FUJITA¹, Rie TAKAOKA¹, Yasuhide MOCHIZUKI⁴, Junya SHITE⁴

¹大阪府済生会中津病院検査技術部, ²竹内医院, ³大阪府済生会中津病院神経内科, ⁴大阪府済生会中津病院循環器内科

¹Department of Clinical Laboratory, Osaka Saiseikai Nakatsu Hospital, ²Takeuchi Clinic, ³Department of Neurology, Osaka Saiseikai Nakatsu Hospital, ⁴Cardiovascular Division, Osaka Saiseikai Nakatsu Hospital

キーワード : echocardiography, nonbacterial thrombotic endocarditis, underlying disease

症例は50歳代男性．主訴は頭痛，左視野障害，既往歴に特記事項なし．運転中に突然左視野障害，頭痛，嘔気が出現したため当院来院．頭部コンピューター断層撮影にて両側小脳，右後頭葉，左前頭葉に脳梗塞を認め，当院神経内科に入院した．塞栓源検索のため経胸壁心臓超音波検査で僧帽弁前尖左房側に18mm大の可動性のある異常構造物を認めた．僧帽弁は逸脱なく，逆流もごく軽度であった．形状から乳頭状弾性線維腫を疑い摘出術が検討されたが，抗凝固療法にて経過観察中の経胸壁及び，経食道心臓超音波検査で異常構造物は，ほぼ消失した．感染兆候はなく，血液培養陰性で，感染性心内膜炎は否定的であったため非細菌性血栓性心内膜炎と診断し，外科治療は回避された．本例では非細菌性血栓性心内膜炎に多く認められるとされる悪性腫瘍や敗血症，自己免疫疾患などに伴う凝固亢進状態を認めなかった．以上，明らかな基礎疾患を有しない非細菌性血栓性心内膜炎の1例を経験し，その診断，治療方針の決定に心エコー図法による詳細な経過観察が有用であった．

A man in his 50s was admitted to our hospital for acute visual disturbance, headache, and vomiting while driving his car. Brain computed tomography imaging revealed multiple cerebral embolisms. Transthoracic and transesophageal echocardiography on admission showed an abnormal mass echo (18 mm in length) attached at the atrial side of the anterior mitral leaflet. The other characteristics of the mitral valve did not show valvular destruction findings, prolapse, or significant regurgitation. There were no inflammatory laboratory findings and blood culture was negative. During anti-coagulation therapy, however, the abnormal mass echo diminished on follow-up echocardiography, which indicated that the mass echo was nonbacterial thrombotic endocarditis (NBTE). Further examination performed to determine the underlying cause of NBTE showed no malignancy, autoimmune disease, or abnormal coagulation status. We herein report a rare case of NBTE without apparent clinical underlying disease, and discuss the usefulness of echocardiography in the diagnosis of this disease.