A 46-year-old man was admitted to our hospital with a 6-month history of recurrent hypoglycemia with an unknown cause. Four months back, he was diagnosed with a complex ulcer in the stomach and duodenum in a local hospital. Physical examination revealed that the liver was swollen with a hard texture and located 5 cm below the costal margin of the abdomen. On admission, his random blood glucose level was 1.6 mmol/L, and routine laboratory tests, including those for liver enzymes, showed normal findings. The levels of tumor markers, including carcinoembryonic antigen, alpha-fetoprotein, carbohydrate antigen 19-9, and neuron-specific enolase, were normal. Magnetic resonance imaging (MRI) of the brain and pituitary gland showed no abnormalities. However, abdominal MRI revealed solid components in the pancreas and multiple masses on the liver (Figure 1A,B,C). We first considered functional neuroendocrine cancer of the pancreas with multiple liver metastases. For blood glucose control, the patient first received multiple transarterial chemoembolization (TACE) sessions to reduce the tumor burden. This resulted in amelioration of the symptoms of hypoglycemia, although they occasionally manifested. Whole-body fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) revealed a slightly hypodense lesion measuring 7.0×6.1 cm2 in diameter in the body of the pancreas. The lesion exhibited significantly different degrees of FDG uptake [ Figure 1D ; maximum standardized uptake (SUVmax): 4.74].