Lipoid pneumonia

Last revised by Adrià Roset Altadill on 29 Mar 2023

Lipoid pneumonia is a form of pneumonia associated with oily or lipid components within the pneumonitis component.

This can either result from:

Patients with a risk of aspiration have a greater risk of lipoid pneumonia, including those with: 

  • neuromuscular disorders

  • esophageal abnormalities

  • cleft palate

The endogenous type can be seen in association with lung cancer 2.

Case reports are emerging in patients who use e-cigarettes (vaping) 12.

Most patients are asymptomatic and often discovered incidentally. 

Macroscopically the affected regions often have a yellowish or golden hue, which is thought to be produced by the liberation of lipid material from alveolar pneumocytes secondary to the inflammatory reaction. 

Lipid-laden macrophages are often seen in histological samples following transthoracic needle biopsy. With exogenous forms, inhaled lipid content (e.g. from aspiration) is phagocytosed by macrophages which fill alveoli. A subsequent acute pneumonitis results which may progress to chronic pneumonitis.

X-ray features are variable 3, and lipoid pneumonia may appear as consolidation, an irregular mass-like lesion, or a reticulonodular pattern.

  • characteristically shows low attenuation within the consolidated areas of around -100 HU reflecting fat content

    • at times the attenuation value may be greater, i.e. around -30 HU and higher than that of subcutaneous fat 10

  • consolidation may have a predilection for the dependent portions of the lungs 3

  • associated ossific foci may be present within the affected region

  • a crazy-paving pattern may also be seen

Not part of routine evaluation. Signal characteristics may reflect fat/paraffin content. usually:

  • T1: high to intermediate signal 7

  • T2: low to intermediate signal 7

Serial radiographs showing stability may be enough in asymptomatic patients with no background history. A biopsy can be performed in some of the cases to ensure the benign nature of the lesion, especially if changes are lipid-poor and imaging features persistent.

The mainstay of management in exogenous types is control and cessation of offending agent.

A fibrotic component can develop in chronic cases.

Other possible complications include:

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Cases and figures

  •  Case 1
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  • Case 2
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  • Case 3: acute exogenous lipoid pneumonia
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  • Case 4: complicated by mycobacteria infection
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  • Case 5
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  • Case 6
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  • Case 7
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  • Case 8: chronic exogenous
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