Chylothorax-induced diaphragmatic herniation: a novel complication of Gorham-Stout syndrome.

A young male with Gorham-Stout syndrome (GSS), a rare lymphovascular disorder causing bone loss, presented with cough, difficulty breathing, and chylous pleural effusion infected with Staphylococcus aureus. Despite thoracic duct ligation, his chylothorax recurred. Imaging showed bone lesions in the sternum and ribs, along with thickened pleura. Electromyography revealed mild bilateral phrenic nerve motor conduction abnormalities. A year later, he developed a symptomatic left diaphragmatic hernia with partial bowel obstruction that required surgical repair. This case highlights the need for early diaphragm monitoring in GSS patients with chylothorax to prevent serious complications.