Porous Diaphragm Syndrome: A Literature Review.

Porous diaphragm syndrome (PDS) is a rare and underrecognized condition characterized by the transdiaphragmatic migration of peritoneal contents into the pleural cavity through defects in the diaphragm, most often affecting the right hemidiaphragm. It is commonly associated with hepatic hydrothorax, peritoneal dialysis-related hydrothorax, and peritoneal carcinomatosis. Despite its anatomical simplicity and the availability of effective surgical treatment, PDS is frequently misdiagnosed, leading to repeated pleural drainage, inappropriate therapies, and treatment delays. This review synthesizes evidence from the past 25 years, drawing from PubMed, Scopus, and Web of Science, with a focus on clinical presentations, diagnostic methods, surgical management, and long-term outcomes. PDS most often presents as recurrent right-sided pleural effusion in cirrhotic or dialysis-dependent patients. Diagnostic approaches include pleural fluid analysis, CT peritoneography, peritoneal scintigraphy, and video-assisted thoracoscopic surgery (VATS), which also serves as the definitive therapeutic modality. VATS enables the direct visualization and repair of diaphragmatic defects with high success rates and low recurrence rates. Surgical correction often allows peritoneal dialysis to be resumed, while cirrhotic patients may benefit from transjugular intrahepatic portosystemic shunt (TIPS) or liver transplantation for long-term control. PDS should be considered in all cases of unexplained, recurrent pleural effusion in patients with underlying intra-abdominal pathology. Early recognition and multidisciplinary intervention, especially through thoracoscopic techniques, are key to improving outcomes and reducing recurrence.