Abstract
The purpose of this paper is to call attention to a group of cases showing the clinical signs of Ayerza's disease (sclerosis of the pulmonary artery) due to another pathologic condition and to offer some points which will aid in differentiating the various pathologic processes which may cause this syndrome. Parkes Weber1 classifies the pathologic conditions associated with "secondary" (symptomatic) forms of polycythemia rubra, and mentions the following classes of cases: It will be seen that under Ayerza's disease, Parkes Weber groups all cases