放射線治療後に多発性脳動脈瘤の発生をみた下垂体腺腫の1例

Multiple Intracranial Aneurysms Following Radiation Therapy for Pituitary Adenoma; A case report

I．はじめに

　放射線治療後に動脈硬化が促進される可能性のあることは旧くから知られている^3）．最近，脳腫瘍の放射線療法後に脳血管障害を発症したとの報告も散見されるが6^13），そのほとんどが閉塞性病変で，出血値病変の報告は極めて稀である^11）．今回われわれは，下垂体腺腫に対する放射線療法後に，くも膜下出血で発症し，新たな脳動脈瘤の形成を認めた症例を経験したので，若干の文献的考察を加え報告する．

A report is made here on a rare case in which occur-rence of multiple cerebral aneurysm was observed after radiotherapy. The case was that of a female aged 51 who was hospitalized with the chief complaint of con-sciousness disorder. The patient was discharged from the hospital 1 year before, after undergoing subtotal ex-tirpation of a tumor through the transsphenoidal sinus in a case of pituitary adenoma, and post-operative radiotherapy (topical 50Gy).

Mild hyperlipidemia associated with hypothyroidism was observed by blood biochemical test during the pa-tient's hospitalization, and multiple cerebral infarction was also observed by CT scanning and MR imaging. Therefore, conservative treatments including intensified endocrine-supplementing treatment, centering on thy-roid hormone, were attempted. The patient's thyroid gland function and hyperlipidemia improved but the consciousness disorder persisted. Exacerbation of the consciousness disorder occurred suddenly 6 weeks after the patient's hospitalization. Subarachnoid hemorrhage and hydrocephalus were observed by CT scanning.Cerebral angiography detected a saccular aneurysm in the trifurcation of the right middle cerebral artery, 3 fusiform aneurysms in the periphery of the right middle cerebral artery, 2 fusiform aneurysms in the posterior cerebral artery and irregularity of wall width in the central artery including the terminal region of the inter-nal carotid artery. These findings were not observed at the initial hospitalization and were considered to have been formed newly afterwards. Further, these findings were observed unexceptionally in all the radiated fields. The patient died 8 weeks after hospitalization, and no autopic finding was obtained.

From the above, we presumed that radiation vasculo-pathy caused by the radiation therapy made one year previously, had led to the formation of multiple cere-bral aneurysms. At present, we think that the hyperli-pidemia which we observed, acted as the exacerbating factor responsible for these aneurysms. In this report, we refer to the problems involved in this case, and we discuss them using pertinent medical literature as reference material.