部分的に退縮が見られた多発性末梢型肺動脈瘤の1例

A case of multiple peripheral pulmonary artery aneuryslns associated with partial regression

　肺動脈瘤はまれな疾患であり，とくに肺動脈末梢部に発生する末梢性肺動脈瘤は肺動脈主幹や左石肺動脈主枝に発生する中枢性肺動脈瘤よりも発生頻度はさらに少なく^1〜3），本邦では21例が報告されているに過ぎない。肺動脈瘤はその診断とともに病因を明確にすることが治療法を決定する上で重要になってくる。病因としては先天的肺動脈壁脆弱，局所感染，外傷，梅毒，結核，敗血症性塞栓、マルファン症候群，肺高血圧等多くのものが含まれている。我々は，両側肺に発生し，喀血をくり返し経過観察中にその一部が退縮した稀な1例を経験したので、文献的考察を加えて報告する。

A case of peripheral pulmonary artery aneurysm was described. Twenty-one cases of peripheral pul-monary artery aneurysm reported in Japan were reviewed.

The patient reported in this literature was 31 year-old man complaining of massive hemoptysis. His chest X-Ray revealed a coin lesion five cm in di-ameter in the left middle lung field. After admis-sion body CT and pulmonary arteriography were performed. Pulmonary arteriography revealed sac-cular dilatation of the left lower pulmonary artery and no early venous filling in the arterial phase. From the above findings, we diagnosed as peripheral pulmonary artery aneurysm of the left lower pul-monary artery.

The pulmonary arteriography performed at two years ago revealed aneurysms of the bilateral lungs. During two years from the first pulmonary arterio-graphy, the spontaneous regression of the aneu-rysms of right lung had occured. It is uncertain why the aneurysm disappeared. It may have been possible that the obstruction of the aneurysm and its organization occured by filling of the aneurysm with thrombus.

Impending rupture of the aneurysm of the left lung was so feared in spite of the normal pulmonary artery pressure that a left lower lobectomy wasperformed as well as a pulmonary aneurysmectomy. Histologic examination of the resected specimen revealed a marked defect of elastic fibers, disap-pearance of the intima and partial adhesion of the thrombus. Even in the region where the arterial wall was relatively untouched, tearing of elastic fibers and deformity of the media accompanying their disappearance were clearly found.

This aneurysm is considered pathogenetically to be congenital wall weakness from the following rea-sons : (1) absence of histologic findings of the re-sected aneurysm implicating specific inflammation. (2) absence of pulmonary hypertension in right heart catheterization data, (3) absence of history of in-fection, syphilis or trauma.

Recently, it has been noted in those cases where the pulmonary aneurysm was involved with Behcet disease and Hughes-Stovin syndrome that multiple aneurysms and systemic thrombophlebitis coexist. In Japan, Hughes-Stovin syndrome was reported in two of 21 cases, and Behcet disease in four cases. More recently, these statistics have increased instead of the decrease in infection.