[A Case of Mixed Neuroendocrine-Non-Neuroendocrine Neoplasm( MiNEN) in the Pancreatic Body Associated with Primary Renal Lymphoma].

A man in his 70s was incidentally found to have a pancreatic body tumor on an abdominal ultrasound. Tumor markers, including CEA, CA19-9, DUPAN-2, and SPan-1 were not elevated. Contrast-enhanced CT revealed a well-defined, hypovascular tumor measuring 25×20 mm diameter without dilatation of the distal pancreatic duct. These findings were atypical for a pancreatic ductal adenocarcinoma or a neuroendocrine tumor. A pathological examination obtained by EUS-FNA confirmed the tumor as a Grade 2 neuroendocrine tumor. Three months later, preoperative CT revealed a lobulated mass in his left kidney. FDG-PET showed mild uptake in the pancreatic tumor and high uptake in the renal mass, suggesting a primary renal malignancy rather than metastasis. High FDG uptake was also identified in enlarged para-aortic lymph nodes near the renal hilum. He underwent distal pancreatectomy and left nephrectomy after a multidisciplinary team discussion. Pathology confirmed a mixed ductal-neuroendocrine-acinar cell carcinoma in the pancreas and a diffuse large B-cell lymphoma in the kidney and lymph nodes. Pancreatic MiNEN is an extremely rare disease, accounting for only about 0.2% of all pancreatic tumors.