腎摘8年後に出現した腎細胞癌胃転移の1例

Gastric Wall Metastasis from a Renal Cell Carcinoma 8 years After Radical Nephrectomy, Report of a Case

要旨　患者は69歳，男性．1993年，腎細胞癌で右腎摘出術を施行した．術後インターフェロン療法を受けたが，1998年，1999年，2000年の三度にわたり肺転移のため部分切除を施行した．2001年5月胸焼けが出現し，胃X線検査，胃内視鏡検査にて15mm大の粘膜下腫瘍様病変を認めた．内視鏡的切除術を施行したところ，回収標本の病理所見と腎癌の原発巣，肺転移巣の病理所見より，腎細胞癌の胃転移と診断した．

　Metastasis of any cancer to the stomach is quite uncommon. Gastric metastasis from renal cell carcinoma, in particular, is extremely rare and is usually discovered at autopsy. Recently, we treated a case of gastric metastasis from a renal cell carcinoma that manifested itself 8 years after radical nephrectomy. In 1993, a 69-year-old man was diagnosed with a right renal cell carcinoma and underwent curative nephrectomy followed by postoperative interferon therapy. In 1998, 1999 and 2000, pulmonary metastases were identified and treated each time by partial lung resection. In May 2001, the patient visited a neighborhood clinic for heartburn. An x-ray examination showed a polypoid lesion in the posterior wall of the middle gastric body. The patient was referred to our hospital, where gastrointestinal endoscopy showed a solitary polypoid lesion about 15 mm in diameter located in the greater curvature of the middle gastric body. Microscopic examination of a biopsy specimen indicated that the lesion was an adenocarcinoma, and submucosal invasion was detected by endoscopic ultrasonography. Endoscopic resection was performed, and histologic examination of the resected specimen confirmed a diagnosis of clear cell renal carcinoma. Histologic similarity between this lesion and the primary tumor and lung metastases led us to consider it an exceedingly rare late recurrence to the gastric wall. Although the location was unusual in this case, late recurrence is characteristic of renal cell carcinoma, so careful long-term follow-up is needed.