History
    A 40-year old mass was admitted due to dyspnea and coughing for 3 days.

Findings
    Chest radiograph shows ill-defined patchy opacities in both lungs sparing the apices. HRCT scans shows symmetric, ill-defined, extensive consolidations with air-bronchogrmas in both lung fields, sparing the peripheral and apical lung zones.

Discussion
    Diffuse pulmonary hemorrhage is a syndrome characterized by the presence of widespread hemorrhage from the pulmonary microvasculature leading to hemoptysis, iron deficiency anemia. Although hemoptysis is commonly seen, dyspnea and cough are more common at presentation. The characteristic radiologic findings include bilateral air-space consolidation or ground glass opacities with sparing the lung apices. However, the consolidation may also be asymmetric or unilateral. The consolidation usually resolves within 2-3 days, being replaced by irregular linear opacities and interlobular septal thickening. CT findings of diffuse pulmonary hemorrhage are similar to plain radiograph; air-space consolidation or ground glass opacities with air-bronchograms, which has a perihilar predominance with a tendency to spare the lung apices.
The differential diagnosis depends on the patient's immune status. The most common causes in the immunocompetent patient are antiglomerular basement membrane disease (Goodpasture's syndrome), collagen vascular disease, and idiopathic pulmonary hemorrhage. In immunocompromised patients, diffuse pulmonary hemorrhage is almost always associated with an underlying infection or lung injury. The common feature histologically is the presence of recent hemorrhage and/or hemosiderin, but this is not specific, and precise diagnosis requires additional clinical, serologic, or pathologic information.

References
1. Primack SL, Miller RR, Muller NL, Diffuse pulmonary hemorrhage: clinical, pathologic, and imaging features. AJR 1995; 164: 295-300
2. Cheah FK, Sheppard MN, Hansell DJ. Computed tomography of diffuse pulmonary hemorrhage with pathologic correlation. Clin Radiol 1993; 48: 89-93