Renal cell carcinoma metastasizing to pancreatic neuroendocrine neoplasm - the second case described in the world literature.

Tumor-to-tumor metastases are very rare events. We report a case of a 64-year-old man who presented with a tumor of the pancreas. The patient underwent partial pancreatectomy. Frozen section diagnosis of the tumor was an endocrine neoplasm. Paraffin block slide examination revealed a tumor consisting of two components: pancreatic endocrine neoplasm at the periphery of the tumor and the central part composed of clear cells with delicate vessels. The results of immunohistochemical stains revealed renal cell carcinoma surrounded by pancreatic endocrine neoplasm, therefore representing an unusual case of renal cell carcinoma metastasizing to a pancreatic endocrine neoplasm.