[A case of metastatic renal tumor originating from lung cancer difficult to distinguish from renal cell carcinoma].

A 66-year-old female underwent left lower lobectomy for her lung cancer (adenocarcinoma) in November 1992, followed by the resection of brain metastasis in October 1993. Later, a left renal tumor with paraaortic lymph node swelling was found by a follow-up abdominal CT. She was treated with left nephrectomy and the resection of the paraaortic lymph nodes in June 1997. The histopathology of the resected tumor and the lymph nodes revealed a metastatic renal tumor originating from the pulmonary adenocarcinoma. There have been 38 reported cases of metastatic renal tumor from lung cancer in the Japanese literature.