Background and Purpose— The biological mechanisms predisposing intracranial saccular aneurysms to growth and rupture are not yet fully understood. Mural cell loss is a histological hallmark of ruptured cerebral aneurysms. It remains unclear whether mural cell loss predisposes to aneurysm growth and eventual rupture. Methods— Sodium dodecyl sulfate decellularized and nondecellularized saccular aneurysm from syngeneic thoracic aortas were transplanted to the abdominal aorta of Wistar rats. Aneurysm patency and growth was followed up for 1 month with contrast-enhanced serial magnetic resonance angiographies. Endoscopy and histology of the aneurysms were used to assess the role of periadventitial environment, aneurysm wall, and thrombus remodeling. Results— Nondecellularized aneurysms (n=12) showed a linear course of thrombosis and remained stable. Decellularized aneurysms (n=12) exhibited a heterogeneous pattern of thrombosis, thrombus recanalization, and growth. Three of the growing aneurysms (n=5) ruptured during the observation period. Growing and ruptured aneurysms demonstrated marked adventitial fibrosis and inflammation, complete wall disruption, and increased neutrophil accumulation in unorganized intraluminal thrombus. Conclusions— In the presented experimental setting, complete loss of mural cells acts as a driving force for aneurysm growth and rupture. The findings suggest that aneurysms missing mural cells are incapable to organize a luminal thrombus, leading to recanalization, increased inflammatory reaction, severe wall degeneration, and eventual rupture.

Object The accurate discrimination between tumor and normal tissue is crucial for determining how much to resect and therefore for the clinical outcome of patients with brain tumors. In recent years, guidance with 5-aminolevulinic acid (5-ALA)–induced intraoperative fluorescence has proven to be a useful surgical adjunct for gross-total resection of high-grade gliomas. The clinical utility of 5-ALA in resection of brain tumors other than glioblastomas has not yet been established. The authors assessed the frequency of positive 5-ALA fluorescence in a cohort of patients with primary brain tumors and metastases. Methods The authors conducted a single-center retrospective analysis of 531 patients with intracranial tumors treated by 5-ALA–guided resection or biopsy. They analyzed patient characteristics, preoperative and postoperative liver function test results, intraoperative tumor fluorescence, and histological data. They also screened discharge summaries for clinical adverse effects resulting from the administration of 5-ALA. Intraoperative qualitative 5-ALA fluorescence (none, mild, moderate, and strong) was documented by the surgeon and dichotomized into negative and positive fluorescence. Results A total of 458 cases qualified for final analysis. The highest percentage of 5-ALA–positive fluorescence in open resection was found in glioblastomas (96%, n = 99/103). Among other tumors, 5-ALA–positive fluorescence was detected in 88% (n = 21/32) of anaplastic gliomas (WHO Grade III), 40% (n = 8/19) of low-grade gliomas (WHO Grade II), no (n = 0/3) WHO Grade I gliomas, and 77% (n = 85/110) of meningiomas. Among metastases, the highest percentage of 5-ALA–positive fluorescence was detected in adenocarcinomas (48%, n = 13/27). Low rates or absence of positive fluorescence was found among pituitary adenomas (8%, n = 1/12) and schwannomas (0%, n = 0/7). Biopsies of high-grade primary brain tumors showed positive rates of fluorescence similar to those recorded for open resection. No clinical adverse effects associated with use of 5-ALA were observed. Only 1 patient had clinically silent transient elevation of liver enzymes. Conclusions Study findings suggest that the administration of 5-ALA as a surgical adjunct for resection and biopsy of primary brain tumors and brain metastases is safe. In light of the high rate of positive fluorescence in high-grade gliomas other than glioblastomas, meningiomas, and a variety of metastatic cancers, 5-ALA seems to be a promising tool for enhancing intraoperative identification of neoplastic tissue and optimizing the extent of resection.

✓Multiple spinal extradural meningeal cysts are rare. To the authors' knowledge, there have been only four reported cases in the world literature. The authors report a case of multiple spinal extradural meningeal cysts in a 31-year-old woman presenting with acute paraplegia. Magnetic resonance imaging of the thoracolumbar spine revealed multiple extradural cystic lesions extending from T-7 to T-8 and from T-12 to L-3. Intraoperative findings demonstrated a white, fibrous, and tense cyst filled with cerebrospinal fluid–like colorless fluid. Excision of the posterior wall of the symptomatic cyst was followed by immediate neurological improvement. The examination of the pathological specimen showed a thick duralike layer of collagen and an inner membrane of arachnoid that is often not found in these lesions. The final diagnosis was based on combined imaging, intraoperative, and histopathological findings. The authors review the literature and discuss the etiological, diagnostic, and therapeutic aspects of this lesion.

The incidence of aSDH associated with SAH is low. Most of the patients with aSDH due to a ruptured aneurysm present in exceptionally poor neurological condition. Nevertheless, rapid surgical treatment of the hematoma and aneurysm obliteration can lead to a favorable outcome. Routine CTA should be performed in all patients presenting with an aSDH associated with SAH and no clear history of trauma.