We report a rare case of chronic expanding hematoma of thorax extended to the neck. An 83-year-old man with a history of Lucite ball plombage and thoracoplasty of bilateral thorax was admitted with numbness of left upper extremity. In 6 months, left supraclavicular fossa was gradually bulged like tumor. The lesion was diagnosed as chronic expanding hematoma. Surgically, Lucite balls were removed with surrounding hematoma debris and fluid, and neck hematoma, which was slightly communicated to the thorax, was extirpated. We discussed the genesis of this hematoma and its extension to the neck.