We present the case report of a 35-year-old man with Gorham's disease (disappearing bone disease, massive osteolysis) with initial clinical findings of small bowel lymphangiomatosis and multicentric osteolysis. The patient, who otherwise was healthy, had a chylothorax develop and he died 9 months later of thoracic and pulmonary complications. An autopsy revealed absence of the proximal thoracic duct and significant lymphangiectatic abnormalities of the pleural, peritoneal, diaphragmatic, splenic, and small bowel tissue with lymphangiomatous masses in the thoracic and mediastinal regions. The findings suggest a subtype of Gorham's disease characterized by a dysplastic lymphatic system. Osteolysis was correlated anatomically with lymphangiectatic tissue, suggesting mediation of osteoclastic resorption via local lymphatic tissue factors.