Gorham's Syndrome, also known as massive osteolysis or "vanishing bone disease" results from lymphangiomatosis with adjacent bone resorption. Chylothorax is a common complication in cases of mediastinal involvement. We report a case of Gorham's Syndrome presenting as chylotamponade successfully treated with pericardial drainage, early parenteral nutritional support, bilateral pleurodesis for chylous effusions, and adjuvant external beam radiation. (C) 2003 by The Society of Thoracic Surgeons.