A case of renal cell carcinoma producing alpha-fetoprotein

69歳男.慢性肝炎の治療で近医に通院中であった.血中α-Fetoprotein(AFP)値が高値を示した為, 腹部超音波断層検査及びCTを施行した.右腎下極に腫瘍を指摘され, 精査加療目的で著者の病院に入院した.画像所見などから右腎細胞癌と診断して根治的右腎摘出術を施行した.病理組織学的所見からAFP産生腎細胞癌と診断した.術後AFP値は漸減し, 術後7週目には正常範囲まで下降した.術後38ヵ月後の現時点において, 画像上は局所再発, 転移を認めず, 肝原発腫瘍や慢性肝炎の増悪も認めていない.AFPの推移と再発・転移に関して外来で経過観察を行っている
Renal cell carcinoma (RCC) producing alpha-fetoprotein (AFP) is a rare condition with only 11 cases reported in Japan to our knowledge. A 69-year-old man was admitted to our hospital for further examination of an incidental right renal tumor. Laboratory tests showed markedly increased serum level of AFP whereas both HBs antigen and anti-HCV antibody were negative. Computed tomography and magnetic resonance imaging imagings showed a right renal tumor but no tumor in liver, testis or lymph node. We performed right radical nephrectomy. Serum level of AFP declined within the normal range 7 weeks after nephrectomy according to its half-life curve. The tumor specimen was composed mainly of granular cells. Immunohistochemical examination of the tumor cells proved the presence of AFP in the cytoplasm. The possibility of AFP as a tumor marker of renal cell carcinoma in this case was presented.