Case Report: Pulmonary artery biopsy findings in a patient with a BMPR2 variant-associated pulmonary arterial hypertension.

Mutations in BMPR2 are the most common genetic cause of heritable pulmonary arterial hypertension (PAH). We report a 47-years-old male with a BMPR2 variant (c.246A > G) who presented with dyspnea and recurrent hemoptysis. Right heart catheterization confirmed PAH with a mean PAP of 46 mmHg, PAWP of 3 mmHg, and PVR of 10.75 WU. A pulmonary artery biopsy was performed to exclude alternative diagnoses such as vasculitis and chronic thromboembolism. Histology showed foam cell accumulation in the intima, infiltration of CD3+ T cells, CD20+ B cells, and CD68+ histiocytes in the intima and media, and mucoid deposition. These findings suggest an active inflammatory component and dysregulation of lipid metabolism in early-stage PAH. Targeted PAH therapy improved symptoms, and resolved hemoptysis after bronchial artery embolization. Although the variant is of uncertain significance, this rare biopsy provides early pathological insights into BMPR2-associated PAH. Further studies are needed to clarify mechanisms linking BMPR2, inflammation, and lipid metabolism in vascular remodeling.