Lipoid pneumonia
Updates to Article Attributes
Lipoid pneumonia is a form of pneumonia associated with oily or lipid components within the pneumonitis component.
This can either result from:
aspiration of oily substances (exogenous lipoid pneumonia) or
endogenous accumulation of lipid substances in the alveoli (endogenous lipoid pneumonia)
Epidemiology
Risk factors
Patients with a risk of aspiration have a greater risk of lipoid pneumonia, including those with:
neuromuscular disorders
oesophageal abnormalities
Associations
The endogenous type can be seen in association with lung cancer 2.
Case reports are emerging in patients who use e-cigarettes (vaping) 12.
Clinical presentation
Most patients are asymptomatic and often discovered incidentally.
Pathology
Macroscopic appearance
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.
Microscopic appearance
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.
Radiographic features
Plain radiograph
X-ray features are variable 3, and lipoid pneumonia may appear as consolidation, an irregular mass-like lesion, or a reticulonodular pattern.
CT
-
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
MRI
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
Treatment and prognosis
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.
Complications
A fibrotic component can develop in chronic cases.
Other possible complications include:
superinfection by non-tuberculous mycobacteria
hypercalcaemia
-<p><strong>Lipoid pneumonia</strong> is a form of pneumonia associated with oily or lipid components within the pneumonitis component.</p><p>This can either result from:</p><ul>-<li><p>aspiration of oily substances (<a href="/articles/exogenous-lipoid-pneumonia">exogenous lipoid pneumonia</a>) or</p></li>-<li><p>endogenous accumulation of lipid substances in the alveoli (<a href="/articles/endogenous-lipoid-pneumonia-1">endogenous lipoid pneumonia</a>)</p></li>-</ul><h4>Epidemiology</h4><h5>Risk factors</h5><p>Patients with a risk of aspiration have a greater risk of lipoid pneumonia, including those with: </p><ul>-<li><p>neuromuscular disorders</p></li>-<li><p>oesophageal abnormalities</p></li>-<li><p><a href="/articles/cleft-palate">cleft palate</a></p></li>-</ul><h5>Associations</h5><p>The endogenous type can be seen in association with <a href="/articles/lung-cancer-3">lung cancer</a> <sup>2</sup>.</p><p>Case reports are emerging in patients who use e-cigarettes (vaping) <sup>12</sup>.</p><h4>Clinical presentation</h4><p>Most patients are asymptomatic and often discovered incidentally. </p><h4>Pathology</h4><h5>Macroscopic appearance</h5><p>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. </p><h5>Microscopic appearance</h5><p>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.</p><h4>Radiographic features</h4><h5>Plain radiograph</h5><p>X-ray features are variable <sup>3</sup>, and lipoid pneumonia may appear as consolidation, an irregular mass-like lesion, or a reticulonodular pattern.</p><h5>CT</h5><ul>-<li>-<p>characteristically shows low attenuation within the consolidated areas of around -100 HU reflecting fat content</p>-<ul><li><p>at times the attenuation value may be greater, i.e. around -30 HU and higher than that of subcutaneous fat <sup>10</sup></p></li></ul>-</li>-<li><p>consolidation may have a predilection for the dependent portions of the lungs <sup>3</sup></p></li>-<li><p>associated ossific foci may be present within the affected region</p></li>-<li><p>a <a href="/articles/crazy-paving">crazy-paving pattern</a> may also be seen</p></li>-</ul><h5>MRI</h5><p>Not part of routine evaluation. Signal characteristics may reflect fat/paraffin content. usually:</p><ul>-<li><p><strong>T1:</strong> high to intermediate signal <sup>7</sup></p></li>-<li><p><strong>T2:</strong> low to intermediate signal <sup>7</sup></p></li>-</ul><h4>Treatment and prognosis</h4><p>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.</p><p>The mainstay of management in exogenous types is control and cessation of offending agent.</p><h5>Complications</h5><p>A fibrotic component can develop in chronic cases.</p><p>Other possible complications include:</p><ul>-<li><p>superinfection by <a href="/articles/pulmonary-non-tuberculous-mycobacterial-infection-3" title="Pulmonary non-tuberculous mycobacterial infection">non-tuberculous mycobacteria</a></p></li>-<li><p><a href="/articles/respiratory-insufficiency" title="respiratory insufficiency">respiratory insufficiency</a></p></li>-<li><p><a href="/articles/cor-pulmonale-2">cor pulmonale</a></p></li>-<li><p>hypercalcaemia</p></li>- +<p><strong>Lipoid pneumonia</strong> is a form of pneumonia associated with oily or lipid components within the pneumonitis component.</p><p>This can either result from:</p><ul>
- +<li><p>aspiration of oily substances (<a href="/articles/exogenous-lipoid-pneumonia">exogenous lipoid pneumonia</a>) or</p></li>
- +<li><p>endogenous accumulation of lipid substances in the alveoli (<a href="/articles/endogenous-lipoid-pneumonia-1">endogenous lipoid pneumonia</a>)</p></li>
- +</ul><h4>Epidemiology</h4><h5>Risk factors</h5><p>Patients with a risk of aspiration have a greater risk of lipoid pneumonia, including those with: </p><ul>
- +<li><p>neuromuscular disorders</p></li>
- +<li><p>oesophageal abnormalities</p></li>
- +<li><p><a href="/articles/cleft-palate">cleft palate</a></p></li>
- +</ul><h5>Associations</h5><p>The endogenous type can be seen in association with <a href="/articles/lung-cancer-3">lung cancer</a> <sup>2</sup>.</p><p>Case reports are emerging in patients who use e-cigarettes (vaping) <sup>12</sup>.</p><h4>Clinical presentation</h4><p>Most patients are asymptomatic and often discovered incidentally. </p><h4>Pathology</h4><h5>Macroscopic appearance</h5><p>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. </p><h5>Microscopic appearance</h5><p>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.</p><h4>Radiographic features</h4><h5>Plain radiograph</h5><p>X-ray features are variable <sup>3</sup>, and lipoid pneumonia may appear as consolidation, an irregular mass-like lesion, or a reticulonodular pattern.</p><h5>CT</h5><ul>
- +<li>
- +<p>characteristically shows low attenuation within the consolidated areas of around -100 HU reflecting fat content</p>
- +<ul><li><p>at times the attenuation value may be greater, i.e. around -30 HU and higher than that of subcutaneous fat <sup>10</sup></p></li></ul>
- +</li>
- +<li><p>consolidation may have a predilection for the dependent portions of the lungs <sup>3</sup></p></li>
- +<li><p>associated ossific foci may be present within the affected region</p></li>
- +<li><p>a <a href="/articles/crazy-paving">crazy-paving pattern</a> may also be seen</p></li>
- +</ul><h5>MRI</h5><p>Not part of routine evaluation. Signal characteristics may reflect fat/paraffin content. usually:</p><ul>
- +<li><p><strong>T1:</strong> high to intermediate signal <sup>7</sup></p></li>
- +<li><p><strong>T2:</strong> low to intermediate signal <sup>7</sup></p></li>
- +</ul><h4>Treatment and prognosis</h4><p>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.</p><p>The mainstay of management in exogenous types is control and cessation of offending agent.</p><h5>Complications</h5><p>A fibrotic component can develop in chronic cases.</p><p>Other possible complications include:</p><ul>
- +<li><p>superinfection by <a href="/articles/pulmonary-non-tuberculous-mycobacterial-infection-3" title="Pulmonary non-tuberculous mycobacterial infection">non-tuberculous mycobacteria</a></p></li>
- +<li><p><a href="/articles/respiratory-insufficiency" title="respiratory insufficiency">respiratory insufficiency</a></p></li>
- +<li><p><a href="/articles/cor-pulmonale-2">cor pulmonale</a></p></li>
- +<li><p>hypercalcaemia</p></li>
Image 8 CT (non-contrast) ( create )
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