脳梗塞を契機に発見された無形性腫瘍性病変の1例

Calcified Amorphous Tumor Diagnosed After Stroke：Report of a Case

はじめに　心臓内腫瘤は腫瘍性病変と非腫瘍性病変に分類され，腫瘍性病変には粘液腫や乳頭状線維弾性腫，横紋筋腫などが含まれる．一方，非腫瘍性病変には血栓や疣贅，無形性腫瘍性病変（calcified amorphous tumor：CAT）などがある．CATは石灰化結節やフィブリンを含む腫瘤であり1），脳梗塞の原因となる2）．また，末期腎不全患者に多く，僧帽弁輪石灰化（MAC）の進行に伴う可能性も示唆されている2）．われわれは，脳梗塞を契機に発見されたCAT例を経験したため，文献的考察を交えて報告する．

Calcified amorphous tumor （CAT）, a non-neoplastic tumor, is rare. Histopathologic features are the presence of calcified nodules in an amorphous background of fibrin. CAT is reported to be associated with renal dysfunction or hemodialysis, and possibly causes cerebral embolism. We report a case of CAT diagnosed after stroke. A 58-year-old male with a 2-year history of hemodialysis was diagnosed with an acute stroke, and was treated medically. Paralysis promptly improved, but transthoracic echocardiography revealed a tumor attached to the posterior mitral leaflet and dense mitral annular calcification. To prevent embolism due to the large tumor, we performed resection of the tumor. Pathological findings showed calcifications surrounded by amorphous fibrous tissue, indicating CAT. Postoperative course was uneventful.