Diagnosis and Management of Functional Pancreatic Neuroendocrine Tumors in Children-A Systematic Review

Background: Functional pancreatic neuroendocrine tumors (FpNETs) are extremely rare in childhood and adolescence, with an incidence of less than 0.1 per million. Since there is currently no systematic review of the literature on FpNETs in children, this study aims to summarize findings from studies focusing on clinical characteristics, diagnostics, treatment modalities, and outcomes. Methods: A systematic review was conducted following the PRISMA guidelines. A literature search was performed using three electronic databases: PubMed, Scopus, and Web of Science. An age filter was used during the search to limit results to childhood and adolescence. There was no limit set in relation to the type and the language of the article. Results: Out of 80,742 records identified, 91 studies met the inclusion criteria and were included in the review. Two studies included patients with insulinoma and gastrinomas, that is, insulinomas and glucagonoma. Of the included studies, 71 were insulinomas, 10 were gastrinomas, 3 were glucagonomas, 6 were VIPomas, and 3 were mixed FpNETs. A total of 163 children with FpNETs were analyzed, with a median age of 12 years. A total of 48 cases were reported in childhood, while 115 cases were reported in adolescence. The results indicate that FpNETs were more prevalent in males. Almost all patients presented with symptoms appropriate to the type of tumor. A significant proportion of tumors were associated with MEN1. In almost all patients, the symptomatology was accompanied by elevated levels of specific hormones. US, CT, PET-CT, MRI, and EUS were the dominant imaging modalities. Surgical approaches and types of resections, depending on the type, association with the syndrome, location, and size of the tumor, were quite heterogeneous. Grade 1 and Grade 2 tumors were nearly equally represented. There was no recurrence in most patients. Conclusions: Early suspicion based on specific clinical symptomatology is essential for timely diagnosis. Accurate localization and size based on modern radiological diagnostics, accompanied by biochemical and genetic testing, are essential for optimal management. Adequate surgical resection offers the best chance of cure, with the lowest risk of recurrence. Additional multicenter registries and studies are needed in the future to better understand tumor behavior, optimal management, and outcomes of FpNETs.