Pathological and Radiological Correlation in Prolonged Myeloperoxidase Anti-neutrophil Cytoplasmic Antibody-related Diffuse Alveolar Hemosiderosis

Abstract

A 60-year-old woman with a 20-year history of myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA)-associated vasculitis visited our hospital due to productive cough and a low-grade fever for several weeks. Thoracic computed tomography demonstrated scattered tiny nodules, patchy consolidation, ground glass opacities, and thickening interlobular septa. On video-assisted thoracic surgery, those abnormalities were found to correspond to the accumulation of hemosiderin-laden alveolar macrophages (AMs) in the alveolar spaces and alveolar septa due to MPO-ANCA vasculitis. The radiological findings persisted for a further two years, indicating the possibility of persistent vasculitis in the lung or evidence of incomplete clearance of hemosiderin-laden AMs.

Keywords: MPO-ANCA; hemosiderin laden alveolar macrophage; hemosiderosis; thoracic computed tomography.

Figure 1.

Chest X-ray (A) on admission showed bilateral nodules with faint infiltration in the whole lung fields, especially in the middle to lower lung fields. Thoracic CT demonstrated scattered tiny nodules in the whole lungs (B, C), and patchy consolidation, ground glass opacities, and thickening of interlobular septa (C) were noted, particularly in the bilateral lower lung lobes.

Figure 2.

Hematoxylin and Eosin staining of biopsied specimens obtained from B8 (A) revealed abundant hemosiderin-laden macrophages in the alveolar spaces. Papanicolaou staining of the bronchial washing fluid retrieved from B8 (B) showed numerous alveolar macrophages that contained the accumulation of intracytoplasmic hemosiderin, which was seen as faint, brown-colored, dense deposits.

Figure 3.

A panoramic view of biopsied specimens from S9/S10 by video-assisted thoracic surgery revealed the presence of a mixture of dense (dotted circle) and faint deposits in the lung on Hematoxylin and Eosin (H&E) staining (A) and iron staining (B). H&E staining showed the accumulation of hemosiderin-laden AMs in the alveolar spaces (C, 100× magnification) that contained brown-col ored pigments (D, 400× magnification) and interlobular septal thickening (D). Iron staining showed AMs with blue granules in the cytoplasm (E). AMs: alveolar macrophages

Figure 4.

Hematoxylin and Eosin staining in a panoramic view showed visceral pleural thickening with a tiny nodule measuring 3 mm in size (A) that contained a small, scarred hematoma (B, 400× magnification). Elastica-Masson staining showed fibrous tissue surrounding the nodule with destruction of the elastic lamina (C, 400× magnification), suggestive of vasculitis.

Figure 5.

Two years after the patient’s first referral, chest X-ray (A) still showed small nodules and faint infiltration in the bilateral middle to lower lung fields. Thoracic CT depicted scattered tiny nodules in the whole lungs (B) together with ground glass opacities and thickening of the interlobular septa in both lower lobes (C).