Pulmonary veins with obstructive venopathy in lungs of patients with PVOD and a case of pulmonary capillary hemangiomatosis. A Longitudinally dissected septal vein with asymmetric intimal and partially occlusive fibrosis. Note the intra-alveolar hemorrhage due to the post-capillary block on the upper half of the photograph. Magnification × 100, EvG. B Pre-septal venule with occlusive intimal fibrosis. Magnification × 100, EvG. C Bronchio-alveolar lavage in a PVOD-patient. Perls-Prussian-Blue staining. Note the siderophages displaying gradually different color-shades (see text). Magnification × 400. D Excessively proliferating alveolar capillaries in a patient with pulmonary capillary hemangiomatosis. Note protrusion of ectatic lumina into the alveoli. Magnification × 200, anti-CD31 staining.