Most patients are asymptomatic and often discovered incidentally.
Lipid-laden macrophages are often seen 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 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
- oesophageal 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 nontuberculous mycobacteria
- respiratory insufficiency
- cor pulmonale
- can be variable 3
- radiological spectrum with consolidation to 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
The mainstay of management in exogenous types is control and cessation of offending agent(s).
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