[A Case of Right Kidney Metastasis of Gastric Cancer].

We experienced a case of kidney metastasis of a gastric tumor. An 81-year-old man underwent distal gastrectomy with D2 lymph node dissection and partial hepatic resection for antral gastric tumor with hepatic infiltration in July 2019. A histological examination showed undifferentiated tubular adenocarcinoma. The final stage was pT4bN1P0H0M0, Stage ⅢB. He rejected the recommended adjuvant chemotherapy. Seven months after surgery, abdominal enhanced CT showed a hypovascular mass, 20 mm in diameter, on the right upper pole of kidney. Eleven months after surgery, CT showed that the mass had enlarged to 35 mm, infiltrated the renal pelvis, and advanced to para-aortic lymph node metastasis. We performed a retroperitoneoscopic partial right nephrectomy and diagnosed kidney metastasis of the gastric tumor. His right flank pain worsened, and radiotherapy(50 Gy)was performed for the mass and para-aortic lymph node metastasis. His right flank pain resolved. Kidney metastasis of the gastric tumor is very rare. Radiotherapy effectively relieves pain.