Intraductal tubulopapillary neoplasm (ITPN) is a rare disease in the pancreas with a better prognosis than pancreatic ductal adenocarcinoma (PDAC) and a different treatment strategy. Therefore, it is important to confirm its diagnosis before the surgery. However, few cases have been diagnosed preoperatively. In this report, we present a case of ITPN that was successfully diagnosed preoperatively.A 70-year-old female patient was incidentally diagnosed with a pancreatic tumor. The patient was asymptomatic, and her blood tests were all within the normal range. A dynamic computed tomography scan showed an indistinct mass with small cysts and a dilated pancreatic duct. The mass was well contrasted in the arterial phase. These findings were not enough to confirm ITPN. Therefore, endoscopic ultrasonography fine needle aspiration biopsy was performed. The specimen had no mucin and the neoplastic cells exhibited a tubulopapillary growth pattern. Moreover, the neoplastic cells were immunohistochemically positive for MUC1, CK7, and CK20, but negative for MUC2, MUC5AC, synaptophysin, and Bcl-10. Consequently, the preoperative diagnosis was confirmed as ITPN. Hence, a subtotal-stomach-preserving pancreaticoduodenectomy was performed, and the patient had a good postoperative course and was discharged after 26 days. Tegafur, gimeracil, and oteracil were administered as postoperative adjuvant chemotherapies for one year. Seventeen months after the surgery, no recurrence has been detected. ITPN and PDAC have different prognoses and treatment strategies. In this report, we experienced a case of ITPN preoperatively diagnosed and successfully treated.