We performed 830 cases of open heart surgery in the past 12 years and two of those cases were complicated by pulmonary aneurysm. The first case was a 21-year-old female with annuloaortic ectasia and treated by partial resection and plication of the pulmonary aneurysm associating of partial resection and plication of the pulmonary aneurysm associating of Bentall's procedure. Pathological examination revealed the findings of Aortitis syndrome, i.e., inflammatory granuloma with round cells infiltration and fragmentation of elastic fibers in the medial as well as adventitial layers. The second case, a reoperation case, was a 44-year-old female with valvular disease, MSR, TSR, Pr and treated by partial resection of the pulmonary aneurysm associating with MVR, TVR, and PA valve plasty. Pathological examination revealed hyalin and necrobiotic degeneration of the media. Both cases involved had pulmonary hypertension suggesting a role for pulmonary hypertension along with organic changes of the vessel in the pathogenesis of the aneurysm.