Thoracic hibernoma located in costodiaphragmatic recess

Hibernoma is a rare, benign soft tissue tumor composed of multiloculated fat cells derived from brown adipose tissue. It can occur in multiple locations, including the neck, thorax, abdomen and musculoskeletal system. Indeed, thoracic hibernomas are extremely rare. We report the CT, MR and histological features of a large hibernoma located in the right costodiaphragmatic recess, a location that, to our knowledge, has not been previously described.