Abstract Introduction Congenital diaphragmatic defects result from incomplete diaphragmatic formation and may remain asymptomatic into adulthood, occasionally predisposing to thoracoabdominal communication. Pancreaticopleural fistula (PPF) is a rare complication of pancreatic disease and is infrequently reported after endoscopic retrograde cholangiopancreatography (ERCP). It arises when pancreatic secretions track into the pleural space through an abnormal ductal or diaphragmatic communication, typically presenting as large or recurrent pleural effusions. Because patients often manifest dyspnea rather than abdominal pain, diagnosis may be delayed or missed. We describe a case of post-ERCP PPF occurring through a congenital left diaphragmatic defect, highlighting the importance of early recognition and multidisciplinary management. Case Presentation A 45-year-old man with choledocholithiasis underwent ERCP with successful stone extraction and was discharged the same day. Within hours, he developed severe epigastric pain radiating to the left flank, accompanied by nausea, tachycardia, and tachypnea. Laboratory studies and imaging confirmed acute pancreatitis. Chest radiography showed a moderate left pleural effusion. Despite thoracentesis and initiation of octreotide therapy, the effusion rapidly recurred, necessitating chest-tube placement. Pleural fluid analysis revealed an exudative effusion with markedly elevated amylase and lipase (1000 U/L each), confirming pancreatic origin. Contrast-enhanced CT demonstrated pancreatic fluid extending from the retroperitoneum through a small left diaphragmatic defect consistent with PPF. The patient underwent surgical drainage of associated abscesses; the diaphragmatic defect subsequently closed spontaneously under conservative therapy, with progressive reduction in drainage and complete radiographic resolution. Discussion PPF can mimic primary pulmonary disease. In patients with recurrent left-sided pleural effusions, markedly elevated pleural amylase should raise suspicion for pancreatic origin. Cross-sectional imaging with CT or MRCP confirms the diagnosis. Treatment includes somatostatin analogues, pancreatic duct stenting, or surgery for refractory cases. Spontaneous closure, as observed here, is rare and underscores the value of coordinated multidisciplinary care. Conclusion Pancreaticopleural fistula, though rare, should remain in the differential for unexplained pleural effusions with elevated amylase. Early recognition and imaging are crucial for delineating the tract and guiding therapy. Multidisciplinary management among pulmonology, gastroenterology, and surgery optimizes outcomes. This case demonstrates that spontaneous closure under conservative therapy is possible, highlighting the spectrum of therapeutic responses and the importance of individualized, coordinated care. This abstract is funded by: None
Rodriguez et al. (Fri,) studied this question.