Pancreatic metastasis from renal cell carcinoma extending into the main pancreatic duct: a case report.

While metastasis to the pancreas is uncommon, it may occur from renal cell carcinomas (RCCs). We here present a case of pancreatic metastasis from RCC extending into the main pancreatic duct (MPD) in a 66-year-old Japanese man. The patient had a history of RCC treated with a radical nephrectomy 17 years previously and was found to have a mass approximately 2 cm in diameter in the body of the pancreas on radiological images. The patient was suspected of having pancreatic metastasis from RCC and underwent a distal pancreatectomy with splenectomy. Histologically, the tumor consisted of cells arranged in trabecular and alveolar structures with clear or eosinophilic granular cytoplasm, compatible with a metastatic RCC. The pancreatic tumor extended into the MPD with the stream of pancreatic juice. This condition is similar to RCC extension into the renal vein and the inferior vena cava. In conclusion, although extension into the MPD may be rare, such a growth pattern may be characteristic of metastases from RCCs.