[Intrathoracic chest wall type lipoma with crescent-shaped mass on computed tomography; report of a case].

An asymptomatic 53-year-old woman was referred to our hospital with a slow-growing intrathoracic tumor after 3 years observation. Chest computed tomography (CT) and magnetic resonance imaging (MRI) showed an intrathoracic crescent-shaped mass measuring 13 x 2.5 cm along the left chest wall. Fatty contents were suggested. Surgical resection was successfully performed by video-assisted thracoscopic surgery. At operation, a yellowish, thinly encapsulated, 10 cm tumor was attached with its pedicle 2.5 cm in diameter to the pleura of the 7th intercostal space. The lesion was a soft mass, pedunculated and numerously lobulated, that caused the crescent form of the mass on chest CT and MRI. Histopathological examination revealed mature lipoma.