[Metastatic renal tumor originating from esophageal carcinoma: a case report]

We report a case of renal metastasis from esophageal carcinoma. The patient was a 74-year-old man, who had undergone an operation for esophageal carcinoma thirteen months previously. He was admitted to our clinic for examination of a right renal mass. Computed tomography (CT) revealed an irregular low density area in the right kidney and angiography showed a hypovascular tumor. Partial nephrectomy was performed. Histological examination revealed squamous cell carcinoma and the diagnosis was metastasis of esophageal carcinoma. Metastatic renal tumors are rarely encountered clinically and, to our knowledge, the present case is only the 16th clinical report of the renal metastasis of esophageal carcinoma in Japan. However, metastasis to the kidney is relatively common at autopsy. It is the fifth most common site of metastasis following the lungs, liver, bones and adrenals. Consequently, patients with malignancy should be followed up while keeping renal metastasis in mind.