Pancreaticopleural and pancreaticomediastinal fistula: a retrospective case series on clinical outcomes of endoscopic stent therapy in 48 patients

Background Pancreaticopleural and pancreaticomediastinal fistulas (PPMF), are rare complications of pancreatitis caused by a disrupted pancreatic duct. Their optimal management remains unclear due to limited clinical data. The aim of this study was to evaluate outcomes of endoscopic stent therapy in patients with PPMF secondary to acute or chronic pancreatitis. Methods A retrospective case series was performed on 59 patients with PPMF treated at Helsinki University Hospital between 2011 and 2024. Final analysis included 48 patients. Diagnosis was based on amylase-rich pleural effusion (> 200 U/L) and/or a fistula tract presented through imaging. The primary treatment method was endoscopic retrograde cholangiopancreatography (ERCP) with transpapillary pancreatic duct (PD) stenting. Treatment success was defined as resolution of pleural fluid and a radiologically identified closure of the fistula. Results The main etiology was alcohol-induced pancreatitis (94%). Fistulas communicated with the left pleural cavity in 54%, right in 21%, both in 19%, and mediastinum in 10% of cases. Endoscopic therapy was successful in 90% of patients, with a median of three (range 1–8; IQR 2) ERCPs per patient. Following stent placement, fistula closure occurred after a median of 2.3 months (range 1–24; IQR 3). In 22 (73%) cases, the stent was positioned beyond the ductal disruption, resulting in treatment success in all cases. Complications were rare, including three mild-to-moderate post-ERCP pancreatitis (1.9%) and a few stent-related events that were treated endoscopically. There were no recurrences. Four patients required surgery due to failed endoscopic therapy. Overall mortality was 27%, unrelated to PPMF. Conclusions Endoscopic stent therapy is a highly effective and safe treatment method for PPMF. Stent placement beyond ductal disruption is associated with successful treatment. These findings support endoscopic therapy as the first-line treatment for PPMF secondary to acute and chronic pancreatitis. Future prospective studies with larger cohorts are needed to confirm these results.