Diffuse Pulmonary Exogenous Lipoid Pneumonitis – An Indicator of Inhalational Exposure to Aerosolized Oils?
Efrat Ofek, Thomas K Waddell, Shaf Keshavjee, David M Hwang. University Health NetworkToronto, Toronto, ON, Canada
Background: Exogenous lipoid pneumonia (LP) is the result of a foreign body type reaction to the presence of exogenous lipid material in the lungs. Exogenous LP is most commonly seen in the setting of aspiration, where it is typically characterized by patchy lesions corresponding to the distribution of the aspirated material. We report here a series of six unusual cases of exogenous LP in which there was diffuse interstitial deposition of exogenous lipoid material associated with severe emphysema, suggestive of inhalation of aerosolized oils.
Design: Cases were identified through review of pathology specimens from patient undergoing lung volume reduction surgery or lung transplantation for severe emphysema, collected between January 2002 and July 2011.
Results: All 6 cases demonstrated similar histological features, consisting of a background of severe emphysema on which there were numerous macrophages containing abundant variably sized, well-delineated intracytoplasmic vacuoles, suggestive of exogenous lipid material and similar to those typically seen in exogenous LP. The vacuoles were admixed with varying amounts of brown-black pigment. These macrophages were diffusely distributed throughout the lung tissue and predominantly interstitial, although similar macrophages were also present within alveolar spaces. On review of the clinical data, the mean age of these patients was 50±4, and all 6 were past or present smokers. Three patients had known alpha-1 antitrypsin deficiency. Three of the patients had a history of marijuana or other illicit inhalational drug use, while four had histories of occupations in which there may have been exposure to aerosolized oil.
Conclusions: Our findings suggest that diffuse exogenous lipoid pneumonitis may be associated with inhalational exposure to aerosolized oils, whether through illicit inhalational drug use or occupational exposure.
Tuesday, March 20, 2012 2:00 PM
Platform Session: Section D, Tuesday Afternoon