カフェイン併用化学療法が奏功した明細胞肉腫の2例

Effective Neoadjuvant Chemotherapy with Caffeine for Clear Cell Sarcoma. Report of Two Cases

　抄録：明細胞肉腫は足部に好発する稀な悪性軟部腫瘍で，再発や転移を来しやすいため予後不良である．また，緩徐に増大するため良性腫瘍と間違われやすく，不適切な切除を受けることが多い．今回われわれはカフェイン併用化学療法が著効した明細胞肉腫の再発および転移の2例を経験した．症例1は13歳の女性で，局所再発例である．術前化学療法に放射線療法を併用し，腫瘍は画像上消失した．広範切除および術後化学療法を行い，術後5年で無病生存中である．症例2は47歳の男性で，局所再発に対して広範切除術を受けたが，多発性の肺転移を生じたため，術後化学療法を目的に当科へ紹介となった．化学療法後肺転移巣は画像上いったんすべて消失した．化学療法後に出現した転移巣を切除後3年で無病生存中である．カフェイン併用化学療法は再発，転移例に対しても有効であり，初回治療時から化学療法を施行することが明細胞肉腫の治療成績の向上につながると考えられた．

　Clear cell sarcoma is a rare malignant tumor of soft tissue and is most commonly encountered in the extremities, especially in the foot and ankle region. Because the tumors are slow-growing and appear to be benign, they are often treated inadequately, and their high rates of recurrence and metastasis worsen the prognosis. We report two cases of clear cell sarcoma treated with caffeine-potentiated chemotherapy. In both cases, the diagnosis was difficult but treatment was effective. Case 1 was in a 13-year-old girl in whom local recurrence of clear cell sarcoma in the chest wall was treated with caffeine-potentiated radiochemotherapy. Tumor size on MRI scans decreased markedly, and the tumor was widely excised. There has been no evidence of recurrence during the five years since the operation. Case 2 was in a 47-year-old man with recurrent clear cell sarcoma of the back and multiple lung metastases. The recurrent mass was widely excised, and the lung metastases were treated by caffeine-potentiated chemotherapy. CT revealed complete resolution of the metastases after treatment. A solitary metastasis in the lung was detected after treatment and was excised. The patient has had no evidence of metastasis during the three years since the metastasectomy. These cases demonstrate the effectiveness of caffeine-potentiated chemotherapy for recurrences and metastasis of clear cell sarcoma. Addition of this treatment to initial treatment should improve the outcome of clear cell sarcoma.