J Korean Radiol Soc.  1998 Mar;38(3):453-458. 10.3348/jkrs.1998.38.3.453.

Squalene Aspiration Pneumonia: Thin-Section CT and Histopathologic Findings

• Lee JS
• Gong G
• Lim TH

• KMID: 2201401
• DOI: http://doi.org/10.3348/jkrs.1998.38.3.453

Abstract

PURPOSE: The purpose of this study was to describe the thin-section computed tomography (CT) findings andhistopathologic findings of squalene aspiration pneumonia.
MATERIALS AND METHODS
Thin-section CT scans wereobtained from nine patients with proven exogenous lipoid pneumonia resulting from aspiration of squalene (derivedfrom shark liver oil). The condition was diagnosed by biopsy (n=3), bronchoalveolar lavage (n=4), or sputumcytology and clinical history (n=2); a clinical history of squalene use was confirmed in all patients. Specimensof transbronchial lung biopsy were also reviewed and compared with thin-section CT findings.
RESULTS
Thin-section CT findings included ground-glass attenuation (n=8), consolidations obliterating vascular marking(n=4), scattered centrilobular ground-glass attenuation (n=2), and interlobular interstitial thickening (n=6).Geographic lobular distribution with peripheral spared lobules was observed in all patients. These diseasesinvolved multiple lobes (n=5) and abnormalities were usually located in the dependent portion of the lung. Inthree cases, histopathological correlation showed that ground-glass attenuation reflected intra-alveolarinfiltration of lipid-laden macrophages with exudative fluid. Interlobular septal thickening representedhyperplasia of type II pneumonocytes with mild fibrosis.
CONCLUSION
On the basis of these results, we concludedthat squalene aspiration pneumonia can be reliably diagnosed by thin-section CT findings particularly when theappropriate history is known.

Keyword

Lung, aspiration; Lung, consolidation; Lung, CT; Lung, fibrosis

MeSH Terms

Biopsy
Bronchoalveolar Lavage
Fibrosis
Humans
Liver
Lung
Macrophages
Pneumonia
Pneumonia, Aspiration*
Sharks
Squalene*
Tomography, X-Ray Computed
Squalene

Figure

• 

  Fig. 1. Case 3. A thirty-three year-old man with a history of taking squalene for one month. During the last week, he had taken more than 10 capsules of squalene through the nose, whereupon a cough and mild dyspnea developed. A. On thin-section CT, geographic lobular distribution of dense lobular consolidation obliterating vascular marking was observed at the superior segments of both lobes. An air-bronchogram is clearly demonstrated by the consolidation. Interposed ground-glass attenuation was peripherally located. B. A photomicrograph (Masson-trichrome stain å original magnification, X 200) of a transbronchial lung biopsy specimen obtained two days after the CT scan shows lipid-laden macrophages (arrowheads) and exudative fluid in the alveolar space. There is no demonstrable innltration or inflammatory cells or interstitial fibrosis.

• 

  Fig. 2. Case 4. A fifty-five year-old male with a history of taking squalene for two months. A. Thin-section CT scans of the right lung obtained at the level of the carina. Dense consolidation obliterating bronchovascular marking is located at the posterior segment of the right upper lobe. An air-bronchogram is visualized by the surrounding air space consolidation. Scattered centrilobular ground-glass attenuation (arrows) is also noted in the anterior segment of the right upper lobe. This may have been caused by scattered droplets of squalene. Interstitial thickening is not definite. B. A photomicrograph (Masson-tric- hrome stain å original magnification, X 200) of a transbronchial lung biopsy specimen obtained 14 days after the CT scan of a. Lipid-laden macrophages (arrowheads) is still observed, but exudate is not. Only a small amount of interstitial fibrosis and hyperplasia of type Π pneumonocytes is noted.

• 

  Fig. 3. Case 2. A fifty-nine year-old man with a history of taking squalene for three years. A. Thin-section CT scans of the right lung were obtained at the level of the right middle lobar bronchus. There is geographically distributed interstitial thickening (arrow) at the lateral segment of the right middle lobe. Involved area is sharply marginated from uninvolved normal parenchyma which is located at the peripheral portions of the lung. Interposing ground- glass attenuation is also noted. B. Photomicrograph (Masson-tric- hrome stain å original magnification, X 200) of a transbronchial lung biopsy specimen obtained nine days after the CT scan of a. shows hyperplasia of type Π pneumonocytes and interstitial fibrosis. Lipid-laden macrophages are scarcely observed.

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