ABSTRACT
Pulmonary veno-occlusive disease (PVOD) and pulmonary capillary hemangiomatosis (PCH) are classified as a distinct subgroup of pulmonary arterial hypertension (PAH) and account for 5% to 10% of histological forms of cases initially considered as idiopathic PAH. Even though the first well-documented case of PVOD was described more than 70 years ago and the first case of PCH more than 30 years ago, the characteristics and pathophysiology of this disease remain poorly understood (1-3). While the pulmonary vascular pathology of idiopathic or familial PAH is characterized by major remodeling of small precapillary pulmonary arteries with typical plexiform lesions, PVOD and PCH preferentially affect the postcapillary pulmonary vessels: the small pulmonary veins and capillaries, respectively (4-6). Despite this histological difference, PVOD and PCH have a clinical presentation very similar to PAH but are characterized by a worse prognosis and the possibility of developing severe pulmonary edema with specific PAH therapy, justifying the importance of diagnosing this disease. A definitive diagnosis of PVOD and PCH require histological analysis of a lung sample (7,8); however, surgical lung biopsy is a high-risk procedure in these patients, and the recent improved characterization of these diseases has permitted to propose a less invasive diagnostic approach (2,9-13).
