대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Lipoid pneumonia

Radiologic Findings

Chest CT scan shows multifocal patchy GGOs with crazy-paving pattern in both lungs, with central portion predominancy.
This patient had taken Omega-3 oil for 5 to 6 years.

Brief Review

Lipoid pneumonia is uncommon and, although it is difficult to determine the precise clinical incidence, autopsy series have reported a frequency of only 1.0–2.5%. However, it is important to be aware of the various radiologic manifestations of lipoid pneumonia because, in the appropriate clinical setting, these findings can be diagnostic. Lipoid pneumonia can be either exogenous or endogenous in cause based on the source of the lipid. Exogenous lipoid pneumonia usually occurs when animal fats or mineral or vegetable oils are aspirated or inhaled, whereas endogenous lipoid pneumonia results from lipid accumulation within intraalveolar macrophages in the setting of bronchial obstruction, chronic pulmonary infection, pulmonary alveolar proteinosis, or fat storage diseases. The development of parenchymal abnormalities in exogenous lipoid pneumonia is dependent on the type, amount, frequency, and length of time of aspirated or inhaled oils or fats. Mineral oil (a mixture of inert, long-chain, saturated hydrocarbons obtained from petroleum) and vegetable-based oils tend to cause minimal to mild inflammatory reactions. On the contrary, animal fats are hydrolyzed by lung lipases into free fatty acids that trigger a severe inflammatory reaction that manifests as focal edema and intraalveolar hemorrhage.
Acute exogenous lipoid pneumonia can manifest radiologically within 30 minutes of the episode of aspiration or inhalation, and pulmonary opacities can be seen in most patients within 24 hours. The opacities are typically ground-glass or consolidative, bilateral, and segmental or lobar in distribution and predominantly involve the middle and lower lobes. Other manifestations of acute exogenous lipoid pneumonia include poorly marginated nodules, pneumatoceles, pneumomediastinum, pneumothorax, and pleural effusions. Pneumatoceles usually occur within regions of ground-glass or consolidative opacities, typically manifest radiologically within 2–30 days after aspiration or inhalation, and are more common in patients who have aspirated or inhaled a large amount of mineral oils or petroleum-based products.
The radiologic manifestations of acute exogenous lipoid pneumonia typically improve or resolve over time. Resolution of opacities is variable and usually occurs within 2 weeks to 8 months. Typically, resolution is complete, although minimal scarring can occur. Similar to acute exogenous lipoid pneumonia, chronic exogenous lipoid pneumonia most frequently manifests as ground-glass or consolidative opacities involving one or more segments, typically with a peribronchovascular distribution and predominant involvement of the lower lobes. Additionally, ground-glass opacities with associated interlobular septal thickening (crazy-paving pattern) with a basilar predominance have also been described.

Please refer to

Case 1069, Case 747, Case 639, Case 554, Case 134, Case 24,

KSTR imaging conference 2018 Spring  Case 5 ,
KSTR Imaging conference 2010 Summer  Case 9 ,
KSTR Imaging conference 2009 Summer  Case 8 ,
KSTR Imaging Conference 2004 Summer  Case 7 ,
KSTR Imaging Conference 2002 Summer  Case 7 ,
KSTR Imaging Conference 2001 Spring  Case 4,

References

1. Bentacourt SL, Martinez S, Rossi SE, Truong MT, Carrillo J, Erasmus JJ, Lipoid Pneumonia – Spectrum of Clinical and Radiologic Manifestations , American Journal of Roentgenology, 2010;194: 103-109

Keywords