RT Journal Article SR Electronic T1 A comparative histological study of pulmonary vascular lesions in lungs of patients With idiopathic or heritable PAH JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP P3406 VO 42 IS Suppl 57 A1 Maria Rosa Ghigna A1 Christophe Guignabert A1 Marc Humbert A1 Peter Dorfmuller YR 2013 UL http://erj.ersjournals.com/content/42/Suppl_57/P3406.abstract AB Although patients with pulmonary arterial hypertension (PAH) carrying a bone morphogenetic protein receptor type 2 (BMPR2) mutation present with symptoms approximately 10 years earlier than noncarriers and show more severely hampered hemodynamics at diagnosis, their histological features have never been investigated in detail and compared with idiopathic PAH. The aim of this work was to explore and compare the histology and morphology of pulmonary vascular lesions between BMPR2 mutation carriers and noncarriers.Five random sections of lung parenchyma from 28 patients, including 15 BMPR2 mutation carriers and 13 noncarriers, were histologically re-evaluated blindly by two experienced pathologists. Density (n/cm2) and appearance of plexiform lesions (Pls) (“atypical Pls”/ typical Pls), inflammation score and arterial thickening were analysed. Our findings revealed a positive trend of Pls density in BMPR2 mutation carriers as compared to noncarriers. So called “atypical Pls” (histologically identified as larger angiodysplastic arterial lesions) were almost exclusively found in the group of BMPR2 mutation carriers.View this table:Table 1Differences in arterial thickening between mutation carriers and non-carriers did not reach statistical significance. No difference in the score of perivascular inflammation was observed between both groups.Our results reveal, for the first time, the existence of distinctive morphologic patterns between lungs with BMPR2-related hPAH and idiopathic PAH. A precise definition of specific histological features may lead to a better understanding of PAH pathogenesis.