We report the case of a 54-year-old male presenting to the emergency department with dyspnea and right-sided chest pain following recent thoracic trauma. He had no significant medical history but showed progressive anemia.
 
A chest X-ray (Figure 1A) revealed right-sided rib fractures and an extensive ipsilateral opacity with extrapulmonary morphology. Chest CT scan (Figures 1B-D) showed a loculated, biconvex collection on the right side, with dependent areas of bleeding, separated from the lung parenchyma by a thin fat-density line (the extrapleural fat sign). These findings confirmed an extrapleural hematoma. The hematoma was successfully drained via a chest tube, leading to clinical improvement.

 
Extrapleural hematomas are rare, occurring in 7.1% of thoracic trauma cases. They result from bleeding between the parietal pleura and endothoracic fascia and are often associated with rib fractures, hemothorax, pneumothorax, and pulmonary contusions.(1)
 
The extrapleural fat sign, seen on CT, is a linear fat-density line separating the pulmonary parenchyma from extrapleural lesions. It corresponds to extrapleural fat thickened and medially displaced in extrapleural pathologies.(2)
 
Recognizing this sign is critical to differentiating extrapleural hematomas from hemothorax, as their management and complications differ.(1,2)
 
AUTHOR CONTRIBUTIONS
 
All of the authors equally contributed to the writing and reviewing of the manuscript.
 
CONFLICTS OF INTEREST
 
None declared.
 
REFERENCES
 
1.            Shankar T, Ameena Ms S, Nagasubramanyam V, Meena R, Sasidharan P. Extrapleural Hematoma: A Rare Sequalae of Thoracic Trauma. Cureus. 2024;16(9):e70506. https://doi.org/10.7759/cureus.70506
2.            Chung JH, Carr RB, Stern EJ. Extrapleural hematomas: imaging appearance, classifica-tion, and clinical significance. J Thorac Imaging. 2011;26(3):218-223. https://doi.org/10.1097/RTI.0b013e3181ebeaba