Pulmonary veno-occlusive disease (PVOD) is a rare cause of severe pulmonary hypertension characterised by poor prognosis. We report the case of a 24-year-old male patient with increasing dyspnea and exercise intolerance treated with calcium channel blockers and glucocorticosteroids, due to suspicion of pulmonary hypertension and interstitial lung disease, until lung biopsy was performed and a diagnosis of PVOD was established on the basis of the histological analysis of the lung biopsy sample. This case highlights that pulmonary veno-occlusive disease is a disorder that is difficult to diagnose and resistant to medical treatment, which is particularly poor prognostic factor. Due to poor response to medical therapy and high mortality in patients with PVOD, understanding the pathogenesis, differentiation with pulmonary arterial hypertension and the search for a new methods of treatment should be the key challenges for modern medicine.