成人型Wilms' tumorの1例 : 本邦報告例の検討

Abstract

23歳女。主訴は右側腹部痛、血尿で、右側腹部に手拳大の腫瘤を触知した。画像診断所見にて右腎に腎実質よりややdensityが高い7.5×7.0cmの充実性腫瘍性病変を認め、中心部に不整形のlow densityが見られた。又、造影CTでは内部が不均一で軽微な造影効果を示し、中心部に壊死性変化を認め、血管造影では腫瘍はhypovascularで不整な走行がみられる腫瘍血管を認めた。腎癌の診断で経腹的に根治的右腎摘出術を行った。病理組織では腫瘍は主にクロマチンに富む短紡錘型の異型核細胞で占められ所々管腔状配列やロゼット状配列を呈し密に増生していた。Blastema cellの増生巣の間には線維芽細胞様の間質細胞が認められた。Blastema cellは間葉系配列が上皮様配列より優勢であることから、Wilms腫瘍、腎芽型と診断した。術後化学療法を行なったが、1年3ヵ月後に肺野に再発を認めた。肺部分切除後に追加化学療法を行い、腎摘後3年4ヵ月経過し再発なく外来通院中である。

The patient was a 23-year-old-woman who was referred to our hospital with chief complaints of right flank pain and macroscopic hematuria. Right radical nephrectomy was performed with the diagnosis of right renal cancer. Histopathological examination revealed Wilms' tumor of favorable histology, stage I according to the National Wilms Tumor Study classification. She received adjuvant chemotherapy consisting of actinomycin D and vincristine at another hospital. One year and three months later, she developed lung metastasis. She underwent partial pulmonary resection, and then received chemotherapy. She is presently disease-free more than forty months after the initial operation. Wilms' tumor is rare in adults and has a poor prognosis compared with that in children. We analyzed 112 cases in the Japanese literature from 1981 to 2004. The mean age was 36.9 years, with males and females equally affected. No difference was found between the left and right sides in frequency of tumor. We also examined the relationship between histological features and prognosis based on 43 Japanese reports. Twenty-two of the 43 (51%) cases had unfavorable histology. The 2-year survival rate with unfavorable histology was 18%, while that with favorable histology was 87%. The 2-year survival rates for stages under II and over III were 67% and 27%, respectively. Based on these findings, we conclude that the prognosis of adult Wilms' tumor is very poor since many patients have unfavorable histology and no effective treatment guidelines have been established.