Late-Onset Pancreatic Metastasis From Renal Cell Carcinoma Mimicking a Neuroendocrine Tumor: A Diagnostic Challenge and Literature Review

Pancreatic metastasis from renal cell carcinoma (RCC) is a rare and often delayed event, frequently resembling primary pancreatic neoplasms such as neuroendocrine tumors, which poses substantial diagnostic challenges. This report describes a case involving a 74-year-old male patient with pancreatic metastasis originating from the left kidney. Seven years earlier, the patient had undergone a left nephrectomy for RCC. Follow-up evaluations after seven years revealed a mass in the pancreatic body, with initial radiological assessments suggesting a provisional diagnosis of a neuroendocrine tumor. Endoscopic ultrasound-guided fine-needle biopsy of the pancreatic lesion, combined with a panel of immunohistochemistry markers, confirmed that the mass was metastatic RCC. A surgical procedure is planned for the patient. This case report presents an uncommon instance of delayed pancreatic metastasis from RCC and reviews the relevant literature on its clinical presentation, diagnostic approaches, and treatment options.