Most patients are asymptomatic and often discovered incidentally.
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 +/- chronic pneumonitis results.
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.
- aspiration risk
- neuromuscular disorders
- esophageal abnormalities
- cleft palate
The endogenous type can be seen in association with lung cancer 2.
A fibrotic component can develop in chronic cases.
Other possible complications include:
- superinfection by non-tuberculous mycobacteria
- respiratory insufficiency
- cor pulmonale
- can be variable 3
- radiological spectrum with consolidation to an irregular mass-like lesion to a reticulonodular pattern
- characteristically show low attenuation within the consolidated areas of ~ -100HU reflecting a fat content (at times the attenuation value may be less i.e. around -30 HU)
- 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
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(s).
- 1. Betancourt SL, Martinez-Jimenez S, Rossi SE et-al. Lipoid pneumonia: spectrum of clinical and radiologic manifestations. AJR Am J Roentgenol. 2010;194 (1): 103-9. doi:10.2214/AJR.09.3040 - Pubmed citation
- 2. Tamura A, Hebisawa A, Fukushima K et-al. Lipoid pneumonia in lung cancer: radiographic and pathological features. Jpn. J. Clin. Oncol. 1998;28 (8): 492-6. doi:10.1093/jjco/28.8.492 - Pubmed citation
- 3. Gaerte SC, Meyer CA, Winer-Muram HT et-al. Fat-containing lesions of the chest. Radiographics. 2002;22 Spec No (suppl 1): S61-78. Radiographics (full text) - Pubmed citation
- 4. Bandla HP, Davis SH, Hopkins NE. Lipoid pneumonia: a silent complication of mineral oil aspiration. Pediatrics. 1999;103 (2): E19. doi:10.1542/peds.103.2.e19 - Pubmed citation
- 5. Kim M, Lee KY, Lee KW et-al. MDCT evaluation of foreign bodies and liquid aspiration pneumonia in adults. AJR Am J Roentgenol. 2008;190 (4): 907-15. doi:10.2214/AJR.07.2766 - Pubmed citation
- 6. Giménez A, Franquet T, Prats R et-al. Unusual primary lung tumors: a radiologic-pathologic overview. Radiographics. 22 (3): 601-19. Radiographics (full text) - Pubmed citation
- 7. Carette MF, Grivaux M, Monod B et-al. MR findings in lipoid pneumonia. AJR Am J Roentgenol. 1989;153 (5): 1097-8. AJR Am J Roentgenol (citation) - Pubmed citation
- 8. Hadda V, Khilnani GC. Lipoid pneumonia: an overview. Expert Rev Respir Med. 2010;4 (6): 799-807. doi:10.1586/ers.10.74 - Pubmed citation
- 9. Franquet T, Giménez A, Rosón N, Torrubia S, Sabaté JM, Pérez C. Aspiration diseases: findings, pitfalls, and differential diagnosis. Radiographics : a review publication of the Radiological Society of North America, Inc. 20 (3): 673-85. doi:10.1148/radiographics.20.3.g00ma01673 - Pubmed