“…The presence of vasa vasorum was described in the inner adventitia, with excessive hyperplasia of the smooth muscle cells in the media and luminal stenosis, surrounded by multiple lymphoid follicles [ 93 ]. Fault-like vertical deviations were noted in the medial layer with atheromatous degeneration and disruption of the elastic fibre [ 4 , 25 , 93 ]. These degenerative changes in the media of the pulmonary arteries with fragmentation of the elastic fibres and pooling of mucopolysaccharides are called “cystic medial necrosis” [ 10 , 14 , 26 , 27 , 37 , 86 , 95 ], which are believed to be the result of progressive injury and repair.…”