Exploring the clinical characteristics and prevalence of the annular pancreas: a meta-analysis.

Background: The annular pancreas (AP) is a rare gastrointestinal congenital malformation, in which malrotation of the pancreatic ventral bud in the seventh week of embryonic development manifests in a partial or complete ring of tissue around the second part of the duodenum.

Methods: The main online medical databases such as PubMed, ScienceDirect, Wiley online library, Web of Science, and EBSCO discovery service were used to gather all relevant studies on the AP.

Results: A total of 12,729,118 patients were analyzed in relation to the prevalence of AP. The pooled prevalence of AP was 0.0045% (95% CI: 0.0021%-0.0077%). The most frequent comorbidity in adults and children was duodenal obstruction, with a pooled prevalence of 24.04% and 52.58%, respectively (95% CI: 6.86%-46.48% and 35.56%-69.31%, respectively). The most frequent operation in adult patients with AP was duodenojejunostomy, with pooled prevalence established at 3.62% (95% CI: 0.00%-10.74%).

Conclusion: The diagnostic complexity of AP is accentuated by its nonspecific clinical symptoms, making accurate identification reliant on imaging studies. Therefore, having a thorough knowledge of the clinical characteristics of the AP and its associated anomalies becomes paramount when faced with this rare congenital condition.