A 75-year-old Japanese man was referred to our hospital to undergo the examination of an enlarged peripancreatic lymph node. Computed tomography (CT) showed a lymph node 47 mm in size that was located above the pancreas head and beneath the liver. Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) of the enlarged lymph node was performed, and an immunohistological examination of the sample confirmed a histological diagnosis of neuroendocrine carcinoma (NEC). The patient refused treatment with chemotherapy and instead chose to undergo observation. However, the lymph node the previously enlarged lymph node was not visible on CT at 12 months after the examination.