Pulmonary capillary hemangiomatosis (PCH) is a rare cause of pulmonary hypertension. At present, only eleven cases have been reported. This report describes the clinical and pathologic findings in three additional cases who presented to the University of Pittsburgh for heart-lung transplantation and integrates the clinical features of all fourteen cases. Clinically, this disorder should be suspected in a patient who presents with pulmonary hypertension, hemoptysis, a reticulonodular infiltrate on chest radiograph, a lung scan showing inhomogeneously enhanced perfusion (particularly in the lower lobes), and pulmonary angiography showing increased peripheral vascularity corresponding to both the radiographic infiltrate and the areas of enhanced perfusion on lung scan. Histologic features consist of nodular proliferation of capillary-sized vessels that infiltrate the pulmonary interstitium, vascular walls, and lumens as well as the alveolar septa. The vascular invasion results in a secondary veno-occlusive phenomenon that explains the clinical confusion with pulmonary veno-occlusive disease.