縦隔悪性芽細胞腫瘍の外科的治療後に急性メガ核芽細胞性白血病を発症した

[Acute Megakaryoblastic Leukemia Developed after the Surgical Treatment of Mediastinal Malignant Germ Cell Tumor].

• Hideki Mitomo
• Toshiharu Tabata
• Ryo Nonomura
• Yutaka Oshima
• Takanobu Sasaki
• Naoya Ishibashi
• Takafumi Sugawara
• Motoyasu Sagawa
• Takashi Kondo
• Kazuhiro Murakami

抄録

26歳男性が縦隔腫瘍の検査のため当院に入院した。胸部CTで巨大な前縦隔腫瘍が気管と右主気管支を狭めていることが判明した。呼吸器疾患のため針生検はできなかったが，精巣に異常なし，血清AFP値が高値であったことから非有声縦隔性生殖細胞悪性腫瘍が強く疑われた．シスプラチン、エトポシド、ブレオマイシンによる1サイクルの化学療法後、縦隔腫瘍は縮小した。経皮生検を試みたが，確定診断がつかず，外科的切除を行った．病理学的には黄嚢腫瘍と肉腫の要素を持つ成熟した奇形腫と診断された。術後5ヵ月後に突然の腰痛と血小板減少が出現した．血液学的検査で急性巨核芽球性白血病と診断され，寛解導入療法と同種造血幹細胞移植を行った．術後12ヶ月経過した現在，いずれの疾患も再発することなく良好である．

A 26-year-old man was admitted to our hospital for an examination of a mediastinal tumor. Chest computed tomography(CT) showed a giant anterior mediastinal tumor narrowing the trachea and right main bronchus. Although needle biopsy could not be done because of patient respiratory condition, non-seminomatous mediastinal germ cell malignant tumor was strongly suspected by high level of serum AFP without no abnormal finding in his testis. After 1 cycle of chemotherapy by cisplatin, etoposide and bleomycin, the mediastinal tumor decreased in size. Percutaneous biopsy was challenged, however, definite diagnosis could not be established and the surgical resection was performed. The tumor was pathologically diagnosed as mature teratoma with elements of a yolk-sac tumor and some sort of sarcoma. Sudden onset of back pain and thrombocytopenia were encountered 5 months after the operation. Hematologic examination confirmed acute megakaryoblastic leukemia, and remission-induction therapy and allogeneic hematopoietic stem cell transplantation were performed. Twelve months after the operation, the patient is well without recurrence of either disease.