[Two cases of idiopathic pulmonary hemosiderosis: analysis of chest CT findings].

Chest CT findings are reported in two cases of idiopathic pulmonary hemosiderosis. In both cases, CT was performed after remission of an acute exacerbation following corticosteroid therapy. Case 1 was a 17-year-old woman with Down's syndrome. Chest radiograph showed diffuse ground-glass like and reticulonodular shadows, which were predominant in the bilateral lower lung fields. Chest CT showed a diffuse increase of lung filed density, especially in the dorsal zone of both lower lobes. Open lung biopsy revealed hemorrhage and numerous hemosiderin-laden macrophages in the alveoli, and in addition, marked fibrous thickening of the alveolar septa. Case 2 was a 7-year-old girl. Chest radiograph showed diffuse micronodular shadows in both lungs. Chest CT showed diffuse poorly-circumscribed micronodular lesions with uniform distribution, and lung field density was normal except for the right upper lobe with patchy infiltrates. Although lung biopsy was not performed, fibrous thickening of the alveolar septa was presumed to be mild even if present, since pulmonary function and blood gas analysis were within normal limits. In these two cases, lung field density of CT seemed to reflect the degree of diffuse fibrous thickening of the alveolar septa, and it is suggested that CT is valuable in the evaluation of fibrous thickening of the alveolar septa secondary to recurrent pulmonary hemorrhages. Comprehensive review of CT findings of idiopathic pulmonary hemosiderosis was also performed.