The present authors report the case of an adult with chronic granulomatous disease who developed an unusual lung fibrosis associated with severe pulmonary hypertension. Histological analysis of a lung biopsy showed a diffuse infiltration with pigmented macrophages without granulomas, which particularly involved the pulmonary arterial and venular walls. Clinical and histological findings were suggestive of pulmonary veno-occlusive disease. Such a clinical association has not been previously described in the literature and might be due to the persistent expression of gp91phox at a very low level. In conclusion, the present case report illustrates a novel manifestation of chronic granulomatous disease.