Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Exogenous lipoid pneumonia (confirmed by open lung biopsy)
- Radiologic Findings
- Initial HRCT images (Fig. 1-2) show multiple patchy and nodular areas of ill-defined ground-glass attenuation and consolidation with mixed smooth intralobular/interlobular septal thickening in both lungs, especially in both lower lungs with somewhat posterior predominance. Mediastinal window setting images (Fig. 3-4) show areas of fat attenuation within consolidation in the posterior lung on each side. Follow up HRCT images (Fig. 5-6) after two months show increased extent of ground-glass attenuation with decreased attenuation of previous consolidative lesions and progressed internal fine reticulation associated smooth intralobular interstitial thickening (crazy-paving lesions) in both lungs with somewhat posterior predominance. Follow up mediastinal window setting images (Fig. 7-8) show several reactive hyperplastic enlargements of lymph nodes in mediastinum and both hila.
- Brief Review
- Exogenous lipoid pneumonia is a pulmonary disorder resulting from chronic aspiration or inhalation of animal, vegetable, or petroleum-based oils or fats. Predisposing factors such as structural abnormalities of the pharynx, esophageal disorders (achalasia, Zenker diverticulum, hiatus hernia, and reflux), neurologic defects, and chronic illness are common. However, in many cases, no predisposing condition is found.
Symptoms include cough, mild fever, shortness of breath, and chest discomfort.
Chest radiographs are usually nonspecific, demonstrating bilateral lower-lobe air-space opacities, mixed alveolar and interstitial opacities, and occasionally poorly marginated focal mass-like lesions that mimic pulmonary neoplasms. If a large amount of lipid has been aspirated, high-resolution CT usually reveals consolidation that is characteristically low in attenuation (-35 to -75 HU), indicating the presence of lipid deposition. However, exogenous lipoid pneumonia can also manifest as geographic ground-glass attenuation; this appearance is most common in patients with chronic mineral oil aspiration. An appearance of ground-glass opacity associated with interlobular septal thickening and intralobular lines (crazy paving) has also been reported. This crazy-paving pattern reflects intraalveolar and interstitial accumulation of lipid-laden macrophages and hyperplasia of type II pneumocytes in the alveolar lining. Centrilobular opacities may also be seen. However, because inflammation or fibrosis may accompany the presence of the lipid material, the CT attenuation of the consolidation need not be low. In some patients, necrosis and cavitation may be present. Diagnosis can be difficult, since many patients do not recall a history of ingestion or inhalation of mineral oil substances. Bronchoalveolar lavage, transbronchial biopsy, or open lung biopsy combined with a history of oil ingestion and radiographic studies are usually diagnostic.
- References
- 1. Sonia L. Betancourt, Santiago Martinez-Jimenez, Sntiago E. Rossi, Mylene T. Truong, Jorge Carrillo, Jeremy J. Erasmus, Lipoid Pneumonia: Spectrum of Clinical and Radiologic Manifestations. AJR 2010; 194:103
2. Santiago E. Rossi, Jeremy J. Erasmus, Mariano Volpacchio, Tomas Franquet, Teresa Castiglioni, H. Page McAdams, Crazy-Paving pattern at Thin-Section CT of the Lungs: Radiologic-Pathologic Overview. RadioGraphics 2003; 23:1509
3. W. Richard Webb, Nestor L. Muller, David P. Naidich, High-resolution CT of the Lung 4th edition
- Keywords
- lung, iatrogenic,