Gastric metastasis from renal cell carcinoma with submucosal invasion treated by surgical full-thickness resection: a case report.

Background: Metastatic gastric tumors are rare and malignant melanoma, breast cancer, lung cancer, and esophageal cancer are common as primary lesions. On the other hand, renal cell carcinoma is easy to metastasize hematogenously to the whole body. However, metastasis to the stomach is rare and the detailed treatment of gastric metastasis is not mentioned. In this study, we report an uncommon case of gastric metastasis from renal cell carcinoma that underwent surgical full-thickness resection and reviewed the literature for treatment options.

Case presentation: The patient was a female in her 60s and in January 2007, she underwent a transabdominal left nephrectomy for clear cell carcinoma of the left kidney. The pathological diagnosis was pT2N0M0 stage II. In October 2017, a total pancreatectomy with D2 dissection was performed for multiple pancreatic masses, in which the pathological diagnosis was pancreatic metastasis of renal cell cancer. In May 2019, an esophagogastroduodenoscopy for heartburn revealed redness and erosion in the greater curvature of the residual gastric body. The pathological diagnosis was gastric metastasis from renal cell carcinoma. No metastatic findings were observed and gastric wedge resection was performed. Pathological diagnosis of the resected specimen showed a 4-mm tumor, mainly within the mucosa and partly extended to the submucosal layer in 500 µm. The resected specimen had a clear resection margin.

Conclusions: In this study, we report a case in which a full-thickness resection was performed for gastric metastasis 12 years after renal cancer surgery and 2 years after pancreatic metastasis surgery. The patient survived 4 years and 8 months after gastric wedge resection. Although gastric metastasis often takes the form of submucosal tumors, it is necessary to select full-thickness resection for R0 resection, even in small and flat lesions.