Fenestrated Anterior Communicating Artery Complex Mimicking an Unruptured Aneurysm: Diagnostic Pitfall.

Anatomical variations often occur in the anterior communicating artery (AComA) complex, and a careful preoperative evaluation is required before repair of this lesion. We report a case of a fenestrated AComA complex mimicking an unruptured cerebral aneurysm. A 49-year-old woman was referred to our hospital under suspicion of unruptured aneurysms of the AComA and the left middle cerebral artery on magnetic resonance angiography (MRA). Additional three-dimensional computed tomographic angiography (CTA) showed the lesion arising from the AComA complex with a maximum diameter of 4.2 mm. Intraoperative findings showed that the putative aneurysm was actually a fenestrated AComA complex as the blood vessels that formed the AComA complex were dilated and meandering. After the operation, MRA and CTA three-dimensional images were reviewed again but we could still not diagnose the lesion as a fenestrated AComA complex rather than an aneurysm. However, in the MRA source image, a secant line in the lesion was the only finding suggestive of a fenestration. The AComA complex is often associated with various vascular malformations, and it is essential to consider this association in the preoperative evaluation. The interpretation of source images may be helpful for accurate diagnosis and surgical planning.

Idiopathic focal calvarial thinning: A case report.

Background: Calvarial bone thinning is a rare clinical entity, with only several cases reported (including Gorham-Stout disease), but the cause is often unknown. Here, we report such a case of unilateral calvarial thinning with an unknown cause. Case Description: A 77-year-old woman undergoing imaging examination for unruptured cerebral aneurysms for the past several years noticed a progressive cranial deformity. Computed tomography revealed progressive thinning of the right parietal bone and cranial deformity but laboratory tests showed no causative findings. A cranioplasty was performed to protect the brain and confirm the pathology. Grossly, pigmentation and deformity were observed on the outer plate of the bone but the inner plate was intact. Pathological examination revealed preserved bone cells and no necrosis. In addition, there were no findings of vascular hyperplasia or malignancy. It appeared that localized osteoporosis had occurred, mainly in the outer plate of the bone, but the cause was unclear. Conclusion: Progressive focal calvarial thinning is rarely reported and the mechanism in this case was unknown. It is important to determine the cause of the bone thinning to evaluate the need for surgical intervention from the viewpoint of brain protection and prevention of cerebrospinal fluid leakage.

Simultaneous intracerebral and subarachnoid hemorrhages caused by multiple infectious intracranial aneurysms treated endovascularly and by microsurgical clipping: illustrative case.

BACKGROUND: Infected intracranial aneurysms are relatively rare but tend to occur in multiple locations. Establishing an optimal treatment strategy for multiple ruptured aneurysms is often challenging, especially when simultaneous ruptures occur in different locations. We report a case of simultaneous intracerebral and subarachnoid hemorrhages caused by the rupture of multiple infected intracranial aneurysms. OBSERVATIONS: A 23-year-old male with a 2-week history of chronic fever presented with sudden onset of severe headache and visual disturbance. Computed tomography showed intracerebral hemorrhage in the right occipital lobe and subarachnoid hemorrhage in the area of the left Sylvian fissure. Further investigation documented Staphylococcus bacteremia, verrucae on the mitral valve, and aneurysms arising from the right posterior cerebral artery (PCA) and the left middle cerebral artery (MCA). A larger aneurysm arising from the PCA was successfully occluded endovascularly, but subsequent endovascular occlusion of the MCA aneurysm was unsuccessful because some important branches were observed extending from the aneurysm. The left MCA aneurysm was then obliterated by angioplastic clipping via left pterional craniotomy. The patient showed a favorable neurological recovery after treatment. LESSONS: In such complex cases of infectious aneurysms, the method and timing of treatment need to be carefully determined based on the medical condition.

Spontaneous regression of a posterior fossa meningioma: A case report.

Background: Since most incidentally discovered meningiomas grow or remain unchanged, spontaneous regression is extremely rare. Here, we report a case of posterior fossa meningioma showing spontaneous regression. Case Description: A 55-year-old female was referred to our hospital because she was diagnosed with a left posterior fossa meningioma (diameter: 1.6 cm) during a brain check-up. The patient was followed up on periodic magnetic resonance imaging studies. Tumor size remained almost unchanged for 2 years but then began to regress. Twelve years after the initial examination, the tumor diameter idiopathically decreased from 1.6 cm to 1.1 cm while the tumor volume decreased from 2.3 cm3 to 0.5 cm3 (about 1/4th the original size). Postmenopausal hormonal imbalances may have been associated with the observed spontaneous regression. Conclusion: Understanding the natural history of meningiomas is essential for a better selection of treatment approaches or appropriate follow-up. This case may provide new insights into the progression of meningiomas.

Extracranial arteriovenous malformation and subsequent contralateral cavernous sinus dural arteriovenous fistula showing abducens nerve palsy: illustrative case.

BACKGROUND: Extracranial arteriovenous malformations (AVMs) are rare clinical entities and on rare occasions cause neurological symptoms. The authors report a case of an extracranial pterygoid AVM and a subsequent contralateral cavernous sinus dural arteriovenous fistula (dAVF) presenting with abducens nerve palsy. OBSERVATIONS: An 80-year-old woman was referred to the authors' hospital with left abducens nerve palsy followed by right ophthalmalgia. Magnetic resonance imaging (MRI) showed abnormal vessel staining in the left pterygoid and the right inferior petrosal sinus (IPS). Cerebral angiography revealed a left pterygoid AVM draining into the right IPS via the cavernous sinus (CS). A dAVF in the right CS was also revealed. The right ophthalmalgia disappeared spontaneously, and, 4 months later, the left abducens nerve palsy also disappeared after conservative management. Follow-up MRI showed spontaneous regression of the AVM and dAVF. The disappearance of the dAVF was considered to be due to spontaneous regression of the left pterygoid AVM and the consequent decrease in venous pressure of the CS, and the symptoms eventually disappeared. LESSONS: The authors treated an extremely rare case of extracranial AVM with dramatic changes in vascular structure and symptoms. Understanding of the pathophysiology between symptoms and dynamic changes in the vascular structure is essential for providing the appropriate treatment.