We report a case of Gorham's disease of the chest wall in a 29-year-old man. A chest radiograph showed osteolysis of the left first, second, and third ribs. CT and MR images revealed a soft tissue mass around the affected ribs. The mass presented as having heterogeneous high signal intensity on T2-weighted MR images, and it showed minimal enhancement on contrast-enhanced MR images. A histologic specimen obtained by incisional biopsy from the left third rib revealed proliferation of lymphangiomatous tissue in the bone marrow. A diagnosis of Gorham's disease was made based on these clinical, radiologic, and histologic findings.