Case 1) A 35-year-old man was admitted to our hospital for detailed examination of a 50-mm pancreas head tumor with surrounding lymph node swelling detected on medical checkup images. Ultrasound-guided lymph node biopsy specimens gave a diagnosis of a nonfunctioning pancreatic neuroendocrine cancer, and adjuvant systemic chemotherapy was given after surgical resection of the tumor. Case 2) A 52-year-old man was admitted to our hospital for detailed examination of an 18-mm pancreas head tumor detected by medical checkup FDG-PET images. Imaging tests gave a diagnosis of a nonfunctioning pancreatic neuroendocrine tumor. He underwent surgical resection, and the tumor was diagnosed as benign pathologically. Both cases showed FDG-PET accumulation in the tumors irrespective of their malignant or benign nature. Increased prevalence of FDG-PET checkup may increase the diagnosis of pancreatic neuroendocrine tumor in asymptomatic subjects.