Giant hibernoma of the thoracic pleura and chest wall

Figure 1 A computerized tomography scan with intravenous contract was obtained of the chest. A: A circumscribed lobulated mass was seen arising from the upper anterior right pleura at the second intercostal space. The mass extended both intra thoracic and extra thoracic; B: The extrathoracic component anteriorly displaced the upper portion of the pectoralis minor muscle (circle).

Figure 2 Pathology showed a specimen with dimensions 10. 5 cm medial to lateral, 7.5 cm superior to inferior and 6 cm anterior to posterior containing lobular, brown fat. A: The specimen with dimensions 10.5 cm medial to lateral, 7.5 cm superior to inferior and 6 cm anterior to posterior; B: Grossly the tumor contained lobular, brown fat.

Figure 3 Microscopic evaluation of the hibernoma is characterized by vacuolated granular eosinophilic cells (hematoxylin-eosin, × 100). The inset (hematoxylin-eosin, × 400) shows a high power view of granular and multivacuolated cells in hibernoma.