대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Pulmonary Fat Embolism

Radiologic Findings

Chest radiograph showed the periphery of the lung to be diffusely consolidated. Chest CT scan performed on the same day of chest PA revealed a diffuse consolidation and ground glass opacity associated with interlobular septal thickening and intralobular interstitial thickening in the peripheral areas of the both lungs (2, 3). Follow-up HRCT showed resolution of the consolidation and ground-glass opacities after 2 weeks (4).

Brief Review

Fat embolism usually occurs after major trauma-associated long-bone fractures. The lung is the most frequently affected organ. The clinical symptoms are variable, but symptoms including respiratory distress, cerebral abnormalities, or petechial hemorrhages are present in some patients.
There are two suggestions regarding the pathophysiology of pulmonary fat embolism. The mechanical theory proposes that fat droplets released from the injured long-bone or from adipose tissue enter the venous system and obstruct the pulmonary vascular bed. The biomedical theory proposed that the embolic fat is derived from the circulating blood lipids. These free fatty acids are directly toxic to pneumocytes and capillary endothelium in the lung, causing interstitial hemorrhage, diffuse alveolar hemorrhage, edema, and chemical pneumonitis.
The pathologic findings of pulmonary fat embolism consist of fat globules within the microvasculature, edema, alveolar hemorrhage, and in certain patients, hyaline membranes formation, or pneumonitis. Fat microglobules can be detected within the alveoli because of alveolar wall damage.
Radiographs may be normal in mild cases, but appear non-segmental distribution of ground-glass attenuation and airspace consolidation associated with interstitial thickening which mimic increased permeability edema. The lung apices are usually less severely involved. Radiographic findings return to normal after 2 days to 2 weeks. The radiologic differential diagnosis includes lung contusion, pulmonary edema, and aspiration.
In our case, the patients had a history of the injection mammoplasty of the breasts one week ago (collagen material?). Sputum staining (Papanicolaou smear, 100x) shows foamy histiocytes, which are including fat microglobules.

References

1. Malagari K, Economopoulos N, Stoupis C et al. High-Resolution CT Findings in Mild Pulmonary Fat Embolism. Chest. 2003;123:1196-1201
2. Choi JA, Oh YW, Kim KH et al. Nontraumatic Pulmonary Fat Embolism Syndrome: Radiologic and Pathologic Correlations. J of Thorc Imaging 2002; 17:167-169

Keywords

Vascular, lung, Embolic, Thromboembolic,