A 21 year old man presented with a right sided pleural effusion. Destruction of the 11th and 12th right ribs and adjacent vertebral bodies was noted on computed tomographic scanning. An open rib biopsy revealed the histopathological changes of Gorham's syndrome. In view of the progressive vertebral destruction and inevitable spinal cord compromise, he was treated with high dose radiotherapy. The process was arrested and he remains well with no signs of recurrence after four years. Pleural effusion and vertebral destruction complicating Gorham's syndrome carry a poor prognosis but, in this case, high dose radiotherapy has been effective in controlling both the effusion and the progressive bony destruction.