腎摘除術後11年目の腎癌大臀筋転移

Metastasis to the gluteus maximus muscle from renal cell carcinoma 11 years after nephrectomy

症例は76歳の男性。11年前に腎癌（淡明細胞癌，G1＞G2，pT3aN0M0）に対する根治的左腎摘除術を行った。10年後に両側肺転移を認め，インターフェロン療法を開始したが，貧血のため中止していたところ，転移から1年後に右臀部の腫瘤を訴えて再診となった。手拳大，弾性硬の腫瘍性病変を触知し，生検で淡明細胞癌を認めた。腎癌右大臀筋転移と診断し，腫瘍血管塞栓術を行ったが，効果不良のため分子標的薬を試みた。

A 76-year-old man presented with a chief compliant of discomfort in the right gluteus region 11 years after the left radical nephrectomy for renal cell carcinoma（clear cell carcinoma, G1＞G2, pT3aN0M0）. A fist sized elastic tumor lesion with distinct margin was observed on palpation. He had received interferon therapy for both lung metastases developed 10 years after nephrectomy, but discontinued it due to adverse events including anemia and CRP elevation. Operation biopsy revealed metastatic carcinoma cells in the right gluteus maximus muscle. The metastatic cells were pathologically diagnosed as clear cell carcinoma, metastasized from the primary renal cell carcinoma. For therapy, we initially embolized tumor vessels on the patient, but the metastatic lesions were gradually increased. We then used molecular target agents（sunitinib and sorafenib）that provided the reduction of the tumor size and symptomatic improvement；however, the molecular targeted therapy was forced to discontinue due to serious complications including born marrow depression and anorexia.