免疫抑制療法未施行の経過中に軽快と増悪を来した心臓サルコイドーシスの1例

A Case of Cardiac Sarcoidosis Showing Spontaneous Remission and Re-exacerbation without Immunosuppressive Therapy during the Course

要旨　患者は47歳，女性．2004年に呼吸困難が出現し，低心拍出を伴う重症心不全を認めた．⁶⁷Gaシンチでの心集積，心臓MRIでのT2高信号像，心筋生検での小円形細胞集簇により慢性心筋炎と診断したが，心不全治療のみで病状は安定し免疫抑制療法は選択しなかった．その後は心機能改善とMRIでのT2高信号像の消失，血中心筋トロポニンの陰性化を認め，心不全徴候なく経過した．2008年に呼吸困難が再現し，高度僧帽弁逆流を伴う心機能低下とともに，⁶⁷Gaシンチでの心集積，MRIでのT2高信号像およびぶどう膜炎，血清ACE活性の高値を認めた．僧帽弁形成術の際の切除心筋組織所見で非乾酪性類上皮細胞肉芽腫を認めたため，心臓サルコイドーシスと診断した．心臓サルコイドーシスは他臓器サルコイドーシスと異なり自然寛解はしないとされ，確診時には全例ステロイド投与が原則である．しかし，病状の軽快と増悪を来す本例での経験から，同症の臨床表現型について再検討する余地がある．

　A 47-year-old woman suffered from heart failure(HF) at first in 2004. Her cardiac function was severely impaired with a left ventricular ejection fraction(LVEF) of 0.22. The intensive in-hospital management using anti-HF medical treatment for 8 months relieved her signs and symptoms from the New York Heart Association function class(NYHA) IV to II. Before discharge from the hospital, her disorder was diagnosed as idiopathic chronic myocarditis because of the findings of myocardial inflammation demonstrated by Ga-67 scintigram and endomyocardial biopsy. She had developed no evidence of systemic sarcoidosis.

　After a stable clinical status with improved LVEF up to 0.47 and negative for serum cardiac troponin T for 3 years, she was re-admitted for HF exacerbation with NYHA IV in 2008. Her LV function had deteriorated again with a LVEF of 0.30 complicated with severe mitral regurgitation due to the tethering apparatus. Positive Ga-67 scintigram, increased serum angiotensin-converting enzyme level and uveitis implying sarcoidosis were found. Myocardial biopsy during the operative intervention of mitral valvoplasty demonstrated cardiac sarcoidosis histologically due to the findings of non-caseating granulomas surrounded with mononuclear inflammatory cells.

　Unlike sarcoidosis suffered in the other organ such as lungs, it has been considered that cardiac sarcoidosis has a straight-forwardly progressive course without the administration of steroid. It should be worthwhile to investigate the pathomechanism of this peculiar clinical history of spontaneous remission and re-exacerbation in this case with cardiac sarcoidosis.