Figure 7: Microscopic findings of the pulmonary vasculature affected by plasma cell myeloma. (a) The pulmonary artery showing marked plasma cell proliferation. The adventitia is predominantly affected (hematoxylin-eosin, original magnification ). (b) A cross-section of the arteriole indicating plasma cell proliferation. The vascular wall is thickened and the lumen becomes narrow (elastica Masson, original magnification ).