左室乳頭筋へ転移したと思われた淡明細胞型腎細胞癌

Metastasis of Clear Cell Renal Cell Carcinoma to the Left Ventricle

腎細胞癌の心内転移は比較的まれであり，右心系からの転移が一般的である．われわれは，腎摘出後の経過中に左室乳頭筋へリンパ行性転移したと思われた淡明細胞型腎細胞癌の1例を経験した．転移の経路など不明な点も多く，文献的考察をふまえ報告する．

Cardiac metastasis from renal cell carcinoma （RCC） is relatively rare. It generally initiates from the right atrium with or without involvement of the inferior vena cava （IVC）. Here, we report a case of metastasis of isolated clear cell RCC to the left ventricular （LV） papillary muscle. An 84-year-old male who had undergone renal resection due to RCC 19 years before, presented to our hospital with suspected LV tumor by echocardiography. The tumor was located near the posterior papillary muscle, with a size of 15×12 mm. The patient underwent resection of the LV tumor. Pathologically, the tumor was diagnosed as clear cell RCC. The postoperative course was stable, and he did not require any chemotherapy. Although there is no definite evidence of the mechanisms of metastasis, the tumor was supposed to metastasize lymphogeneously.