Fibrocellular

The pathogenesis of PTTM starts with the formation of microscopic tumor cell emboli, which cause small pulmonary vessel injury and induce local activation of coagulation and recruitment of inflammatory markers, eventually leading to fibrocellular intimal proliferation.[ 1 4 8 9 ] The resultant stenosis of the pulmonary capillaries and arterioles increases pulmonary vascular resistance causing PH.