Renal Cell Carcinoma Metastasis To Neuroendocrine Pancreas Tumor: Case Report And Literature Review

The coexistence of two primary neoplasm in one patient is not unusual and two different cancers may even arise at the same anatomic site. However, a metastasis from one tumor to another is significantly rare. A 73-year-old woman, after right-hand nefrectomy 20 years ago because of kidney tumor (no data available) observed for 6 years due to numerous, stable changes in pancreas shown in computer tomography. The latest CT scan confirmed disease progression: numerous PET-CT confirmed neuroendocrine tumors (PNET) clinically without hormonal activity. CT scan suggested metastatic tumor of kidney origin. Complete pancreas resection with splenectomy has been performed. Postoperative histopathological examination revealed NET G1 in pancreas and renal cell carcinoma matastases to neuroendocrine tumor. The diagnosis was confirmed by immunohistochemical staining. Renal cell cancer (RCC) is the most common primary tumor metastasizing to the pancreas, however this is the first report of metastases to neuroendocrine pancreatic tumors. The average time from radical nefrectomy to appearance of metastases to other organs (including pancreas) is 8-10 years. Patients with a history of RCC should undergo a long-term follow-up to detect and evaluate metastasis to pancreas and other organs, but the awareness of the phenomenon of tumor to tumor metastasis is important to avoid an incorrect diagnosis when encountering unusual morphologic features in pancreatic mass.