Tokuda Takaho, Tajiri Seiji, Ueda Yutaka, Ohmori Yuki, Mukasa Akitake
Department of Neurosurgery, Minamata City General Hospital and Medical Center, Kumamoto.
Department of Neurosurgery, Miyazaki Prefectural Nobeoka Hospital, Nobeoka.
Surg Neurol Int. 2022 Apr 29;13:175. doi: 10.25259/SNI_282_2022. eCollection 2022.
Segmental arterial mediolysis (SAM) is a condition in which an aneurysm is formed by causing lysis of the media and remodeling of blood vessels. Short-term recurrence has been reported in abdominal aortic aneurysms. Cerebral aneurysms have been suggested to form in a short period not only in the abdominal cavity but also in the intracranial arteries in SAM.
A 36-year-old pregnant woman at 35 weeks' gestation developed sudden headache and disorientation. Head magnetic resonance imaging showed a small amount of subarachnoid hemorrhage in the right ambient cistern. A fusiform cerebral aneurysm was found in the periphery of the right superior cerebellar artery, and small saccular aneurysms were found in the periphery of the right posterior cerebral artery and left posterior inferior cerebral artery. After delivery of the fetus, endovascular embolization of the ruptured aneurysm was performed. However, 10-week postoperatively, she developed sudden headache. Hemorrhage was found in the fourth ventricle, and enlargement of the left posterior inferior cerebellar artery (PICA) peripheral aneurysm and disappearance of the right posterior cerebral artery peripheral aneurysm were confirmed. A ruptured aneurysm in the peripheral left PICA was removed after trapping. Intraoperatively, an unruptured thrombosed aneurysm that was not visualized by imaging was also removed. Histopathological examination showed no calcification or inflammation, rupture of the internal elastic lamina, and lack of segmentation, and SAM was diagnosed.
In atypical dissecting aneurysms, SAM should be considered as a differential diagnosis. Systemic examination and short-term follow-up are also necessary.
节段性动脉中层溶解（SAM）是一种通过引起中层溶解和血管重塑而形成动脉瘤的病症。腹主动脉瘤已有短期复发的报道。有人提出，在SAM中，不仅在腹腔内，而且在颅内动脉中，脑动脉瘤也可在短时间内形成。
一名35周妊娠的36岁孕妇突然出现头痛和定向障碍。头部磁共振成像显示右侧环池少量蛛网膜下腔出血。在右侧小脑上动脉周围发现一个梭形脑动脉瘤，在右侧大脑后动脉和左侧小脑后下动脉周围发现小囊状动脉瘤。胎儿分娩后，对破裂的动脉瘤进行了血管内栓塞治疗。然而，术后10周，她突然头痛。在第四脑室发现出血，并确认左侧小脑后下动脉（PICA）周围动脉瘤增大，右侧大脑后动脉周围动脉瘤消失。在进行血管夹闭后切除了左侧PICA周围破裂的动脉瘤。术中还切除了一个影像学未显示的未破裂血栓形成动脉瘤。组织病理学检查显示无钙化或炎症、内弹力层破裂且无节段性，诊断为SAM。
在非典型夹层动脉瘤中，应考虑SAM作为鉴别诊断。全身检查和短期随访也是必要的。
