Objective: Rare disease Background: Pulmonary artery aneurysm (PAA), defined as a pathologic dilatation of the PA greater than 1.5-fold the normal diameter, is a rare complication of Beh & ccedil;et disease. It is due to a weakening of the vessel wall for a great vessels' vasculitis, often asymptomatic and incidentally diagnosed on imaging studies. However, if ignored, it can lead to life-threatening complications such as rupture and massive hemoptysis. We report the case of a giant fast-growing PAA in a young patient with a history of Beh & ccedil;et disease in which an inadequate follow-up and poor patient information could had led to life-threatening complications. Case Report: A 37-year-old man with a history of Beh & ccedil;et disease presented to our Emergency Department with hemoptysis due to a right inferior lobar artery aneurysm measuring 52x33 mm. The aneurysm was detected years before, measuring 18 mm, but the patient and physicians missed the subsequent follow-up. After several attempts at embolization, the multidisciplinary board suggested to proceed with surgical intervention. Surgery was performed with an extracorporeal circulation system kept on stand-by due to the high hemorrhagic risk. By opening the fissure, the dilatation of the inferior lobar artery was clearly identified up to the origin of the middle lobar branch. Thus, a lower-middle bilobectomy was performed after the introduction of a suction cannula in the aneurysm, which facilitated its emptying and the subsequent maneuvers. Conclusions: PAA is a rare disease, generally treated with medical therapy or interventional procedures. However, giant and fast-growing aneurysms are more likely to entail complications and often required immediate treatment. In this case, primary surgical intervention with a pulmonary bilobectomy appeared mandatory to avoid life-threatening events.