CT-Visible Venous Fat Embolus Associated With a Femoral Shaft Fracture in a Polytrauma Patient: A Case Report

Venous fat emboli are uncommon but important radiological findings in patients with long-bone fractures, and direct visualization on computed tomography (CT) is rarely reported. We report the case of a 34-year-old man with polytrauma, reported to be hemodynamically stable, admitted after a motorcycle road traffic accident. Initial radiography demonstrated a complete, displaced fracture of the proximal third of the left femoral shaft. Whole-body trauma CT revealed a fat-attenuation intravascular lesion within the distal left external iliac vein extending into the proximal left common femoral vein, with an attenuation value of approximately -81 Hounsfield units, consistent with a venous fat embolus. The lesion persisted in the same venous location across the available non-contrast, arterial-phase, and portal venous-phase images. Thoracic CT angiography showed no pulmonary arterial filling defect or acute pulmonary parenchymal abnormality on the available images. Abdominopelvic CT also demonstrated a superior polar splenic laceration measuring more than 3 cm in depth, associated with perisplenic hemoperitoneum, consistent with grade III splenic injury according to the American Association for the Surgery of Trauma classification. No definite active contrast extravasation was identified on the available arterial, portal venous, and delayed-phase images. Orthopedic fixation of the femoral fracture was subsequently performed; however, detailed follow-up data, including respiratory evolution, neurological status, laboratory data, splenic injury management, and discharge outcome, were not documented in the available medical record. This case highlights the importance of systematic venous assessment on whole-body trauma CT in patients with long-bone fractures and emphasizes the distinction between a CT-visible venous fat embolus and fat embolism syndrome, which remains a clinical diagnosis requiring appropriate clinical correlation.