Intraductal tubulopapillary neoplasm (ITPN) of the pancreas with invasive cancer misdiagnosed as a mesenteric cyst for 12 years: a case report and literature review.

Introduction: An intraductal tubulopapillary neoplasm (ITPN) depicts a distinct entity in the subgroup of premalignant epithelial tumors of the pancreas. Due to the rarity of ITPN, information regarding the disease is currently limited. We present herein a case of pancreatic ITPN with invasive cancer that was misdiagnosed as a mesenteric cyst during a 12-year follow-up period.

Case Report: A 23-year-old female initially presented with an incidental asymptomatic 4-cm retroperitoneal cystic lesion in 2005. For 12 years of surveillance, the lesion remained largely unchanged in size (4-5 cm). In 2017, the cystic lesion was found to have grown to 9 cm. The pre-operative diagnosis was highly suggestive of a benign lesion. However, after total resection of the mass was performed, the final diagnosis was pancreatic ITPN with invasive cancer. The patient recovered uneventfully and is disease-free without recurrence at the time of this report (12 months post-surgery).

Conclusion: The clinicopathologic features of ITPN remain unclear due to its rarity, thus making diagnosis difficult. Clinicians should always consider the possibility of ITPN for cystic lesions located at the retroperitoneum near the tail of the pancreas. More data are needed to understand the disease's long-term outcome to identify clinical and radiological features that can be useful for its diagnosis.